diff --git a/PERFORMANCE.md b/PERFORMANCE.md
index d30884a..d496dfe 100644
--- a/PERFORMANCE.md
+++ b/PERFORMANCE.md
@@ -94,3 +94,11 @@
 改动将 members 同步改为局部状态和串行事务队列；自动保存暂缓，其他元素本地编辑继续，成功响应与持久化基线做三方合并后再保存编辑。Core PR #16 增加源画布局部坐标的 positions 字段及 member_positions 能力，坐标和归属在一个事务保存，支持时省掉前置 PATCH。版本及幂等保护保留。DOM/Hook 延迟响应、丢失响应和版本冲突场景已验证；尚未将模拟的一次 POST 当作线上耗时改善。
 
 Core PR #16 已由用户合并为 2207c85；push #946、PR #947、主线 #949、部署 #950 均成功。前端 a240507 已在 main。23:13:30（Asia/Shanghai）开始安排指定父图 icon 拖放的真实验收；需要刷新以重新检测能力，实测结果待记录核对后补充。
+
+## 首次上传及能力协商复核
+
+23:15–23:16 的真实日志中，新 JPEG 原图 393,301 字节、1280×2276，上传约 8.5 秒；其预览 125,545 字节，首响应等待 5,913.9ms，正文传输 748.1ms，总计 6,662ms。同期 profile/workspaces/小快照也出现约 5–7 秒等待首响应，不能将全部时间归因于图片处理。随后无认证公网健康探测也复现秒级等待：curl 约 1.73/4.24 秒；Node 新建连接 DNS 20ms、TCP 累计 200.4ms、TLS 累计 3,574.6ms、总计 4,808.3ms，同连接复用请求仅 275.4/187.1ms。ECS 内部健康请求约 120.35/13.92/1.81ms。该对照表明冷连接/公网路径存在明显成本，但不是历史每个请求的同期分段追踪，不能声称已定位全部 8.5 秒或修复公网丢包。
+
+能力协商 2 秒截止与约 1,989ms 的服务端路由耗时接近，且真实三次移动前仍有仅 position 变化的 PATCH。现移除短截止并禁止把网络错误永久缓存为“不支持”；慢响应和失败预取回归均保持原子成员移动。后端三笔事务各移动 1 个节点，总数、非位置内容与版本递增均正确。
+
+首次上传改为本地即时预览 + 后台原图上传，服务端确认后保存引用，远端预览加载完才切换显示。该改动消除空画布等待，不将即时显示误报为网络上传已完成或服务端延迟已消失。实际交互复测待用户操作后补充。
diff --git a/README.md b/README.md
index d1cbc3a..e957b14 100644
--- a/README.md
+++ b/README.md
@@ -134,3 +134,5 @@ Headless Canvas API 的拆包方案保留在本地忽略的 `docs/HEADLESS_CANVA
 拖放后元素保持落位，旁边显示局部同步状态；其他元素仍可编辑和拖动。移动中的节点及分区几何暂时受保护，归属事务排队使用最新版本。期间的本地编辑在响应到达后合并，再自动保存。响应丢失时重试复用同一请求和幂等键；明确版本冲突则先重读版本，避免重复移动或覆盖其他编辑。
 
 Core `subgraphs.member_positions` 能力启用时，最终落点（源画布局部坐标）与归属通过一次 members POST 原子保存，单纯拖放不再先 PATCH 坐标。旧后端仍使用先保存坐标再迁移的兼容流程，但不显示整屏等待遮罩。Core 配套 PR #16 已合并并部署为 2207c85；刷新页面后会重新检测并启用新接口能力。
+
+上传图片时立即在画布显示本地预览，并在后台上传原始文件；上传成功才把稳定附件引用加入快照。服务端预览加载完成前继续显示本地图片，避免网络等待期间空白。失败保留文件供重试/取消，重试沿用同一幂等键；本地 blob URL 不保存到服务端。
diff --git a/VALIDATION.md b/VALIDATION.md
index b5d2f78..1f41e2c 100644
--- a/VALIDATION.md
+++ b/VALIDATION.md
@@ -62,3 +62,9 @@
 - TypeScript 和 83 项单元测试通过。新增 DOM/Hook 场景覆盖：原子成员移动一次 POST/无前置 PATCH、延迟响应期间编辑和拖动其他节点、快照合并保留编辑、撤销/重做保留单一归属、丢失响应以相同 body/key 重试、412 重读版本后新命令重试、连续跨分区移动排队、旧后端兼容。
 - 实际 ReactFlow DOM 手势验证 icon 跨分区后出现元素旁同步提示，无整屏同步遮罩；其他元素可继续拖动，服务器确认后位置不回退。既有 AI、连线、框、图片回归通过。无浏览器访问（沿用用户要求）。
 - 最终隔离生产构建通过。Core push #946、PR #947、主线 #949、部署 #950 均成功，包含 Go 测试/构建、数据库迁移和 PostgreSQL 集成测试；PR #16 已合并为 2207c85 并部署。Core 不在本机编译。真实 icon 拖放验收仍待用户操作后的记录核对，不将发布成功当作实际性能实测。
+
+## 慢能力响应与首次上传
+
+生产复核发现 capabilities 请求约 1,989ms，原先 2 秒客户端截止可能误将慢响应缓存为不支持。已删除该短截止，网络错误清除缓存并重试；只有成功响应明确未声明能力才走旧流程。DOM 回归增加 2.1 秒能力响应、预取失败后重试的场景，均保持原子移动、无前置 PATCH。
+
+上传 DOM 回归覆盖：网络未确认前本地图片已显示、可添加其他内容、快照没有 blob URL、原始附件引用与 assetId 正确、远端预览加载后释放本地 URL、失败保留文件、同键重试只创建一个节点、取消/卸载清理与原图比例。TypeScript、83 项单元测试与隔离生产构建通过。生产新上传的交互体验及修正后的能力协商仍需用户刷新后实测。
diff --git a/src/components/canvas/canvas-image.tsx b/src/components/canvas/canvas-image.tsx
new file mode 100644
index 0000000..1bb4cb9
--- /dev/null
+++ b/src/components/canvas/canvas-image.tsx
@@ -0,0 +1,9 @@
+"use client";
+import { createContext, useContext } from "react";
+export const ImagePreviews = createContext<{ sources: Map<string,string>; loaded: (id: string) => void }>({ sources: new Map(), loaded: () => {} });
+export function CanvasImage({ id, src, title, className }: { id: string; src?: string; title: string; className: string }) {
+  const previews = useContext(ImagePreviews), local = previews.sources.get(id);
+  const remote = <img loading="lazy" decoding="async" className={className} src={src} alt={title} draggable={false} referrerPolicy="no-referrer" onLoad={() => previews.loaded(id)} />;
+  if (!local || local === src) return remote;
+  return <div style={{position:"relative",width:"100%",height:"100%",minHeight:0,flex:1,borderRadius:"inherit"}}>{remote}<img className={className} src={local} alt="" aria-hidden draggable={false} style={{position:"absolute",inset:0,pointerEvents:"none"}} /></div>;
+}
diff --git a/src/components/canvas/graph-canvas.tsx b/src/components/canvas/graph-canvas.tsx
index 5cd5177..845f488 100644
--- a/src/components/canvas/graph-canvas.tsx
+++ b/src/components/canvas/graph-canvas.tsx
@@ -1,5 +1,7 @@
 "use client";
-import { uploadCanvasImage } from "@/lib/canvas-assets";
+import { useImageUploads } from "./use-image-uploads";
+import { ImagePreviews } from "./canvas-image";
+import { displayID } from "@/lib/canvas-tree";
 
 import { useCallback, useEffect, useMemo, useRef, useState, type ChangeEvent } from "react";
 import {
@@ -59,7 +61,7 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
   const [tool, setTool] = useState<"select" | "hand">("select");
   const [error, setError] = useState(initial.error);
   const [branchRequest, setBranchRequest] = useState<BranchRequest | null>(null);
-  const [imageUploading, setImageUploading] = useState(false);
+  const [demoImageUploading, setImageUploading] = useState(false);
   const [iconPicker, setIconPicker] = useState(false);
   const [resizing, setResizing] = useState<string | null>(null);
   const [rotating, setRotating] = useState<string | null>(null);
@@ -82,6 +84,16 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
   const ai = useCanvasAI(board.workspace_id, board.id, !!snapshot, tree);
   const state = { present: { ...tree.rootDocument, nodes: tree.views.nodes, edges: tree.views.edges } };
   const treeRef = useRef(tree); treeRef.current = tree;
+  const uploads = useImageUploads(board.workspace_id, (job, asset) => {
+    const current = treeRef.current, document = current.current.current.get(job.owner);
+    if (!document || current.busy || current.rootDocument.schema_version < document.schema_version) throw new Error("canvas_busy");
+    if (document.nodes.length >= 500) throw new Error("当前画布已达到 500 个节点。");
+    if (job.edge && !document.nodes.some((node) => node.id === job.edge!.source)) throw new Error("源节点已移动或删除，请重新添加图片。");
+    const node = { ...job.node, data: { ...job.node.data, src: asset.url, ...(document.schema_version === 2 ? { assetId: asset.id } : {}) } };
+    current.dispatch({ type: "replace", document: { ...document, nodes: [...document.nodes, node], edges: [...document.edges, ...(job.edge ? [job.edge] : [])] } }, job.owner);
+    if (!current.current.current.get(job.owner)?.nodes.some((item) => item.id === node.id)) throw new Error("canvas_busy");
+  });
+  const imageUploading = demoImageUploading || uploads.active;
   function dispatch(action: CanvasAction) {
     if (action.type === "undo" || action.type === "redo") { void treeRef.current[action.type]().catch((error) => setError(error.message)); return; }
     treeRef.current.dispatch(action);
@@ -93,7 +105,14 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
     return () => input?.removeEventListener("cancel", cancel);
   }, []);
   const { nodes: displayNodes, edges } = state.present;
-  const nodes = displayNodes.map((node) => { const ref = tree.views.nodeRefs.get(node.id); const blocked = ref && tree.protectedNodes(ref.boardId).has(ref.id); return blocked ? { ...node, draggable: false, deletable: false, connectable: false } : node; });
+  const pendingUploadNodes = uploads.jobs.filter((job) => job.status !== "uploaded").flatMap((job) => {
+    const ref = tree.views.boards.get(job.owner); if (!ref) return [];
+    return [{ ...job.node, id: displayID(board.id,job.owner,job.node.id), position: { x: ref.origin.x+job.node.position.x*ref.scale,y:ref.origin.y+job.node.position.y*ref.scale }, width:job.node.width!*ref.scale,height:job.node.height!*ref.scale,style:{...job.node.style,width:job.node.width!*ref.scale,height:job.node.height!*ref.scale},selected:false,draggable:false,selectable:false,connectable:false,deletable:false }];
+  });
+  const nodes = [...displayNodes.map((node) => { const ref = tree.views.nodeRefs.get(node.id); const blocked = ref && tree.protectedNodes(ref.boardId).has(ref.id); return blocked ? { ...node, draggable: false, deletable: false, connectable: false } : node; }), ...pendingUploadNodes];
+  const uploadDisplayID = (job: typeof uploads.jobs[number]) => job.status === "uploaded" ? [...tree.views.nodeRefs].find(([,ref])=>ref.id===job.node.id)?.[0] || displayID(board.id,job.owner,job.node.id) : displayID(board.id,job.owner,job.node.id);
+  const imagePreviews = { sources: new Map(uploads.jobs.map((job) => [uploadDisplayID(job),job.localURL])), loaded: (id: string) => { const job = uploads.jobs.find((job) => uploadDisplayID(job)===id);if(job) uploads.loaded(job.node.id); } };
+
   const frameFeedback = useMemo(() => {
     const names = new Map(nodes.filter((node) => node.data.kind === "frame").map((node) => [node.id, node.data.title]));
     const counts = new Map<string, number>();
@@ -292,10 +311,23 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
     }
     const request = pendingImage.current; pendingImage.current = null;
     const kind = imageKind.current;
+    if (snapshot) {
+      try { uploads.start(file, (src) => {
+        const current = treeRef.current;
+        if (request) {
+          const ref = current.views.nodeRefs.get(request.id); if (!ref) throw new Error("源节点已移动或删除，请重新添加图片。");
+          const draft = branchCanvasNode(current.current.current.get(ref.boardId)!,ref.id,request.direction,"image",src,request.at ? {x:(request.at.x-ref.origin.x)/ref.scale,y:(request.at.y-ref.origin.y)/ref.scale}:undefined);
+          return {owner:ref.boardId,node:draft.nodes.at(-1)!,edge:draft.edges.at(-1)};
+        }
+        if(current.rootDocument.nodes.length + uploads.jobs.filter((job)=>job.owner===board.id&&job.status!=="uploaded").length>=500)throw new Error("当前画布已达到 500 个节点。");
+        const node=makeCanvasNode(kind,center(),src);if(kind==='plain-image')node.data.title=file.name.slice(0,300);
+        return {owner:board.id,node};
+      });setTool("select"); } catch(error) {setError(errorText(error));}
+      return;
+    }
     setImageUploading(true);
     try {
-      const uploaded = snapshot ? await uploadCanvasImage(api, board.workspace_id, file, file.name) : null;
-      const src = uploaded?.url || await new Promise<string>((resolve, reject) => {
+      const src = await new Promise<string>((resolve, reject) => {
         const reader = new FileReader();
         reader.onload = () => resolve(String(reader.result));
         reader.onerror = () => reject(new Error("无法读取图片。"));
@@ -305,11 +337,9 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
       if (kind === "plain-image" && !request) {
         size = await new Promise((resolve, reject) => {
           const image = new window.Image();
-          const localSource = uploaded ? URL.createObjectURL(file) : src;
-          const clean = () => { if (uploaded) URL.revokeObjectURL(localSource); };
-          image.onload = () => { const scale = Math.min(1, 480 / image.naturalWidth, 480 / image.naturalHeight); clean(); resolve({ width: Math.max(24, Math.round(image.naturalWidth * scale)), height: Math.max(24, Math.round(image.naturalHeight * scale)) }); };
-          image.onerror = () => { clean(); reject(new Error("无法读取图片尺寸。")); };
-          image.src = localSource;
+          image.onload = () => { const scale = Math.min(1, 480 / image.naturalWidth, 480 / image.naturalHeight); resolve({ width: Math.max(24, Math.round(image.naturalWidth * scale)), height: Math.max(24, Math.round(image.naturalHeight * scale)) }); };
+          image.onerror = () => reject(new Error("无法读取图片尺寸。"));
+          image.src = src;
         });
       }
       if (request) createBranch(request, "image", src); else addNode(kind, src, size, kind === "plain-image" ? file.name : undefined);
@@ -362,12 +392,14 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
 
   return (
     <div className={`${styles.editor} ${tool === "hand" ? styles.handMode : ""}`}>
+      <ImagePreviews.Provider value={imagePreviews}>
       <NodeEditing.Provider value={editing}>
         <FrameFeedback.Provider value={frameFeedback}>
         <EdgeEditing.Provider value={{ begin: beginEdit, patch: tree.patchEdge, active: new Set([...tree.views.edgeRefs].filter(([id, ref]) => ai.activeEdges.has(ref.boardId + "/" + ref.id)).map(([id]) => id)) }}>
         <ReactFlow<CanvasNode> nodes={nodes} edges={edges} nodeTypes={nodeTypes} edgeTypes={edgeTypes}
           onBeforeDelete={async ({ nodes: removing }) => {
             if (tree.busy || tree.transactionBusy) return false;
+            if (removing.some((node) => { const ref=tree.views.nodeRefs.get(node.id);return uploads.jobs.some((job)=>job.status!=="uploaded"&&(node.data.subgraph?.boardId===job.owner||ref?.boardId===job.owner&&ref?.id===job.edge?.source)); })) return false;
             const linked = removing.filter((node) => node.data.subgraph);
             const parents = subgraphParents(tree.current.current);
             const referenced = removing.filter((node) => {
@@ -435,6 +467,7 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
         </EdgeEditing.Provider>
         </FrameFeedback.Provider>
       </NodeEditing.Provider>
+      </ImagePreviews.Provider>
       <div className={styles.topRight}>
         <div className={`${toolbar.surface} ${styles.toolbar}`} role="toolbar" aria-label="图谱视图控制">
           <IconButton icon={Undo2} label="撤销" disabled={!tree.canUndo || tree.busy} onClick={() => dispatch({ type: "undo" })} />
@@ -479,7 +512,8 @@ function CanvasEditor({ board, snapshot }: { board: Board; snapshot?: CanvasSnap
         <p>⌘ / Ctrl + Z 撤销，Shift + ⌘ / Ctrl + Z 重做。</p>
         <p>可通过右上角导出 JSON 备份。</p>
       </div>
-      {imageUploading && <p className={styles.imageUploadStatus} role="status">正在上传图片…</p>}
+      {demoImageUploading && <p className={styles.imageUploadStatus} role="status">正在读取图片…</p>}
+      {uploads.jobs.filter((job)=>job.status!=="uploaded").map((job)=><NodeToolbar key={job.node.id} nodeId={displayID(board.id,job.owner,job.node.id)} isVisible position={Position.Top}><div className={`${styles.memberSync} nodrag nopan`} role="status" aria-label="图片上传状态">{job.status==="failed"?<>上传未完成 <button title={job.error} onClick={()=>uploads.retry(job.node.id)}>重试</button><button onClick={()=>uploads.remove(job.node.id)}>取消</button></>:"上传中…"}</div></NodeToolbar>)}
       <BranchMenu request={branchRequest} close={closeBranch} choose={chooseBranch} />
       {iconPicker && <IconPicker close={() => setIconPicker(false)} choose={(name, label) => {
         if (tree.rootDocument.nodes.length >= 500) { setError("当前图谱已达到 500 个节点。"); return; }
diff --git a/src/components/canvas/material-node.tsx b/src/components/canvas/material-node.tsx
index 12fb013..167b7c4 100644
--- a/src/components/canvas/material-node.tsx
+++ b/src/components/canvas/material-node.tsx
@@ -1,4 +1,5 @@
 "use client";
+import { CanvasImage } from "./canvas-image";
 import { managedImageSource } from "@/lib/canvas-v2";
 
 import { useContext, useRef } from "react";
@@ -26,7 +27,7 @@ export function MaterialNode(props: NodeProps<CanvasNode>) {
     <TransformableNode {...props} className={`${styles.node} ${selected ? styles.selectedNode : ""}`}>
       <header className={styles.nodeHeading}><Icon size={13} /><NodeTitle id={id} title={data.title} selected={selected} /></header>
       <Handle type="target" position={Position.Left} className={styles.legacyHandle} isConnectable={false} />
-      {data.kind === "image" ? <img loading="lazy" decoding="async" className={styles.image} src={managedImageSource(data.src, preview)} alt={data.title} draggable={false} referrerPolicy="no-referrer" /> : (
+      {data.kind === "image" ? <CanvasImage id={id} className={styles.image} src={managedImageSource(data.src, preview)} title={data.title} /> : (
         <CanvasTextEditor id={id} data={data} selected={selected} />
       )}
       <Handle type="source" position={Position.Right} className={styles.legacyHandle} isConnectable={false} />
diff --git a/src/components/canvas/plain-image-node.tsx b/src/components/canvas/plain-image-node.tsx
index 9474a6f..0fa42db 100644
--- a/src/components/canvas/plain-image-node.tsx
+++ b/src/components/canvas/plain-image-node.tsx
@@ -1,4 +1,5 @@
 "use client";
+import { CanvasImage } from "./canvas-image";
 import { managedImageSource } from "@/lib/canvas-v2";
 import { useViewport, type NodeProps } from "@xyflow/react";
 import type { CanvasNode } from "@/lib/canvas";
@@ -7,5 +8,5 @@ import styles from "./canvas.module.css";
 export function PlainImageNode(props: NodeProps<CanvasNode>) {
   const { zoom } = useViewport();
   const preview = (props.width || 320) * zoom * (typeof window === "undefined" ? 1 : window.devicePixelRatio || 1) <= 1024;
-  return <TransformableNode {...props} className={styles.plainImageFrame}><img loading="lazy" decoding="async" className={styles.plainImage} src={managedImageSource(props.data.src, preview)} alt={props.data.title} draggable={false} referrerPolicy="no-referrer" /></TransformableNode>;
+  return <TransformableNode {...props} className={styles.plainImageFrame}><CanvasImage id={props.id} className={styles.plainImage} src={managedImageSource(props.data.src, preview)} title={props.data.title} /></TransformableNode>;
 }
diff --git a/src/components/canvas/use-canvas-tree.ts b/src/components/canvas/use-canvas-tree.ts
index 483eddf..0854e43 100644
--- a/src/components/canvas/use-canvas-tree.ts
+++ b/src/components/canvas/use-canvas-tree.ts
@@ -117,8 +117,18 @@ export function useCanvasTree(root: string, workspace: string, initial: CanvasDo
     for (const [boardId, document] of current.current) update(boardId, { type: "nodes", changes: document.nodes.map((node) => ({ type: "select", id: node.id, selected: view.current.nodeRefs.get(id)?.boardId === boardId && view.current.nodeRefs.get(id)?.id === node.id })) });
   };
   const read = async (boardId: string, signal?: AbortSignal) => decodeSnapshot(await api<CanvasSnapshot>(canvasPath(workspace, boardId), { headers: { Accept: CANVAS_ACCEPT }, signal }));
+  function supportsMemberPositions(): Promise<boolean> {
+    if (!snapshot) return Promise.resolve(false);
+    if (!memberCapability.current) {
+      const capability: Promise<boolean> = api<{ subgraphs?: { member_positions?: boolean } }>(canvasPath(workspace, root) + "/capabilities", { headers: { Accept: CANVAS_ACCEPT } })
+        .then((value) => value.subgraphs?.member_positions === true)
+        .catch((error) => { if (memberCapability.current === capability) memberCapability.current = null; throw error; });
+      memberCapability.current = capability;
+    }
+    return memberCapability.current;
+  }
   useEffect(() => {
-    memberCapability.current = snapshot ? api<{ subgraphs?: { member_positions?: boolean } }>(canvasPath(workspace, root) + "/capabilities", { headers: { Accept: CANVAS_ACCEPT }, signal: AbortSignal.timeout(2000) }).then((value) => value.subgraphs?.member_positions === true).catch(() => false) : Promise.resolve(false);
+    void supportsMemberPositions().catch(() => { /* A failed prefetch is retried on demand, never cached as unsupported. */ });
   }, [root, workspace, !!snapshot]);
   async function ensure(boardId: string, recursive = false, ancestors = new Set<string>()): Promise<void> {
     if (ancestors.has(boardId) || ancestors.size > 8) throw new Error("subgraph_cycle");
@@ -266,7 +276,7 @@ export function useCanvasTree(root: string, workspace: string, initial: CanvasDo
           for (const [id, remote] of refreshed) install(id, remote);
           publish(next); job.refresh = false;
         }
-        const atomic = await memberCapability.current;
+        const atomic = await supportsMemberPositions();
         await flush(atomic === true);
         const bases = new Map(job.participants.map((id) => [id, writers.current.get(id)!.document]));
         const source = current.current.get(job.source)!;
diff --git a/src/components/canvas/use-image-uploads.ts b/src/components/canvas/use-image-uploads.ts
new file mode 100644
index 0000000..6efd431
--- /dev/null
+++ b/src/components/canvas/use-image-uploads.ts
@@ -0,0 +1,46 @@
+"use client";
+import { useEffect, useRef, useState } from "react";
+import { api, errorText } from "@/lib/api";
+import { uploadCanvasImage, type CanvasAsset } from "@/lib/canvas-assets";
+import type { CanvasDocument, CanvasNode } from "@/lib/canvas";
+export type ImageUploadDraft = { owner: string; node: CanvasNode; edge?: CanvasDocument["edges"][number] };
+export type ImageUploadJob = ImageUploadDraft & { file: File; localURL: string; key: string; status: "uploading" | "failed" | "uploaded"; error?: string; controller: AbortController; ready?: Promise<void> };
+
+/** Local previews never enter the canvas document or an autosave payload. */
+export function useImageUploads(workspace: string, commit: (draft: ImageUploadDraft, asset: CanvasAsset) => void) {
+  const pending = useRef(new Map<string, ImageUploadJob>());
+  const [jobs, setJobs] = useState<ImageUploadJob[]>([]);
+  const mounted = useRef(true), onCommit = useRef(commit); onCommit.current = commit;
+  const changed = () => { if (mounted.current) setJobs([...pending.current.values()]); };
+  function remove(id: string) { const job = pending.current.get(id); if (!job) return; job.controller.abort(); URL.revokeObjectURL(job.localURL); pending.current.delete(id); changed(); }
+  useEffect(() => { mounted.current = true; return () => { mounted.current = false; for (const job of pending.current.values()) { job.controller.abort(); URL.revokeObjectURL(job.localURL); } pending.current.clear(); }; }, []);
+  async function run(job: ImageUploadJob) {
+    if (job.status === "uploading") return;
+    job.status = "uploading"; job.error = undefined; job.controller = new AbortController(); changed();
+    try {
+      const [asset] = await Promise.all([uploadCanvasImage(api, workspace, job.file, job.file.name, job.controller.signal, job.key), job.ready || Promise.resolve()]);
+      if (!mounted.current || pending.current.get(job.node.id) !== job || job.controller.signal.aborted) return;
+      onCommit.current(job, asset); job.status = "uploaded"; changed();
+    } catch (error) { if (mounted.current && pending.current.get(job.node.id) === job && !job.controller.signal.aborted) { job.status = "failed"; job.error = errorText(error); changed(); } }
+  }
+  function start(file: File, draft: (localURL: string) => ImageUploadDraft) {
+    const localURL = URL.createObjectURL(file);
+    let value: ImageUploadDraft;
+    try { value = draft(localURL); } catch (error) { URL.revokeObjectURL(localURL); throw error; }
+    const job: ImageUploadJob = { ...value, file, localURL, key: crypto.randomUUID(), status: "failed", controller: new AbortController() };
+    pending.current.set(job.node.id, job); changed();
+    // Browser decoding runs locally, concurrently with the original-byte upload.
+    if (job.node.data.kind === "plain-image") {
+      job.ready = new Promise<void>((resolve,reject) => {
+      const image = new window.Image(); image.onload = () => {
+        if (pending.current.get(job.node.id) !== job) { resolve(); return; }
+        const scale = Math.min(1,480/image.naturalWidth,480/image.naturalHeight);
+        const size = { width: Math.max(24,Math.round(image.naturalWidth*scale)), height: Math.max(24,Math.round(image.naturalHeight*scale)) };
+        job.node = { ...job.node, ...size, style: { ...job.node.style, ...size } }; changed(); resolve();
+      }; image.onerror = () => reject(new Error("无法读取图片尺寸。")); image.src = localURL;
+      });
+    }
+    void run(job);
+  }
+  return { jobs, active: jobs.some((job) => job.status === "uploading"), start, retry: (id: string) => { const job = pending.current.get(id); if (job) void run(job); }, remove, loaded: (id: string) => { if (pending.current.get(id)?.status === "uploaded") remove(id); } };
+}
diff --git a/src/lib/canvas-assets.ts b/src/lib/canvas-assets.ts
index 57042ac..076ba66 100644
--- a/src/lib/canvas-assets.ts
+++ b/src/lib/canvas-assets.ts
@@ -1,10 +1,9 @@
 type Request = <T>(path: string, options?: RequestInit) => Promise<T>;
 export type CanvasAsset = { id: string; url: string; width: number; height: number; bytes: number; mime_type: string };
 export const ASSET_LIMIT = 20 * 1024 * 1024;
-export async function uploadCanvasImage(request: Request, workspace: string, file: Blob, name: string, signal?: AbortSignal): Promise<CanvasAsset> {
+export async function uploadCanvasImage(request: Request, workspace: string, file: Blob, name: string, signal?: AbortSignal, key = crypto.randomUUID()): Promise<CanvasAsset> {
   if (!file.size || file.size > ASSET_LIMIT) throw new Error("asset_too_large");
   const form = new FormData(); form.append("image", file, name);
-  const key = crypto.randomUUID();
   const send = () => request<CanvasAsset>(`workspaces/${encodeURIComponent(workspace)}/assets`, { method: "POST", headers: { "Idempotency-Key": key }, body: form, signal });
   let asset: CanvasAsset;
   try { asset = await send(); } catch (error) {
diff --git a/tests/canvas-member-scenario.mjs b/tests/canvas-member-scenario.mjs
index a8a972c..87c55eb 100644
--- a/tests/canvas-member-scenario.mjs
+++ b/tests/canvas-member-scenario.mjs
@@ -5,18 +5,22 @@ export async function canvasMemberScenario({root,act,h,useCanvasTree,makeCanvasN
  const frame=makeCanvasNode('frame',{x:100,y:100});frame.id='frame';frame.data.subgraph={boardId:child};
  const icon=makeCanvasNode('icon',{x:10,y:20});icon.id='moving';
  const other=makeCanvasNode('text',{x:950,y:100});other.id='other';
- let records,tree,posts,saves,release,mode,receipt,key,body,capability=true;
+ let records,tree,posts,saves,release,mode,receipt,key,body,capability=true,capMode="",capCalls=0;
  const json=(v,status=200)=>new Response(JSON.stringify(v),{status,headers:{'content-type':'application/json'}});
  function Fixture(){tree=useCanvasTree(parent,'w',records.get(parent).document,records.get(parent));return null;}
  const reset=async(nextMode='success')=>{
   await act(async()=>{root.render(null);await tick();});localStorage.clear();
   records=new Map([[parent,{version:1,document:{...emptyCanvas(),schema_version:2,nodes:[structuredClone(frame),structuredClone(other)]}}],[child,{version:1,document:{...emptyCanvas(),schema_version:2,nodes:[structuredClone(icon)]}}]]);
-  posts=[];saves=[];release=null;mode=nextMode;receipt=null;key=null;body=null;
+  posts=[];saves=[];release=null;mode=nextMode;receipt=null;key=null;body=null;capMode=nextMode;capCalls=0;
   if(mode==='queued'){const second=structuredClone(icon);second.id='moving-two';second.position={x:100,y:20};records.get(child).document.nodes.push(second);mode='delayed';}
   mock(async(url,options={})=>{
    const parts=new URL(url,'http://localhost').pathname.split('/'),id=parts[6],suffix=parts.slice(8).join('/'),method=options.method||'GET';
    if(suffix==='ai/runs')return json({runs:[]});
-   if(suffix==='capabilities')return json({subgraphs:{member_positions:capability}});
+   if(suffix==='capabilities'){
+    capCalls++;if(capMode==='slowcap'){await new Promise(r=>setTimeout(r,2100));if(options.signal?.aborted)throw new DOMException('Aborted','AbortError');}
+    if(capMode==='cap-failure'&&capCalls===1)throw new TypeError('network unavailable');
+    return json({subgraphs:{member_positions:capability}});
+   }
    if(!suffix&&method==='GET')return json(structuredClone(records.get(id)));
    if(!suffix&&method==='PATCH'){
     assert.equal(options.headers['If-Match'],`"${records.get(id).version}"`);
@@ -40,7 +44,7 @@ export async function canvasMemberScenario({root,act,h,useCanvasTree,makeCanvasN
   });
   await act(async()=>{root.render(h(Fixture));await tick();await tick();});
  };
- const wait=async(check,label)=>{for(let i=0;i<60;i++){if(check())return;await act(async()=>{await new Promise(r=>setTimeout(r,30));});}throw new Error('Timeout '+label);};
+ const wait=async(check,label)=>{for(let i=0;i<120;i++){if(check())return;await act(async()=>{await new Promise(r=>setTimeout(r,30));});}throw new Error('Timeout '+label);};
  const start=async()=>{
   await act(async()=>{tree.select(child+'::moving');tree.setDragging(true);tree.nodesChanged([{type:'position',id:child+'::moving',position:{x:950,y:200},dragging:false}]);tree.setDragging(false);void tree.moveMembers(parent,'frame',child,parent,['moving'],[parent,child]);await tick();});
   await wait(()=>posts.length,'move admission');
@@ -78,6 +82,9 @@ export async function canvasMemberScenario({root,act,h,useCanvasTree,makeCanvasN
  await act(async()=>{release();await tick();});await wait(()=>!tree.memberJobs.length,'queue drained');
  assert.equal(saves.length,0);assert.equal(tree.rootDocument.nodes.filter(n=>n.id.startsWith('moving')).length,2);assert.equal(tree.current.current.get(child).nodes.length,0);
  console.log('PASS member queue: unrelated cross-frame drops serialize versions without extra coordinate PATCH');
+ await reset('slowcap');await start();await wait(()=>!tree.memberJobs.length,'slow capability move');assert.equal(saves.length,0,'A slow capability response must not trigger legacy PATCH fallback');
+ await reset('cap-failure');await start();await wait(()=>!tree.memberJobs.length,'capability retry');assert.equal(capCalls,2);assert.equal(saves.length,0,'A failed prefetch is retried rather than cached as unsupported');
+ console.log('PASS member capabilities: responses slower than two seconds and transient prefetch errors retain atomic moves');
  capability=false;await reset();await start();await wait(()=>!tree.memberJobs.length,'legacy move');assert.equal(saves.length,1,'Old backend retains the coordinate save');assert.equal(JSON.parse(posts[0].body).positions,undefined);
  console.log('PASS member compatibility: capability-gated positions and legacy two-request fallback');
  capability=true;await reset('delayed');
diff --git a/tests/canvas-ui-check.mjs b/tests/canvas-ui-check.mjs
index 77defb9..bd434eb 100644
--- a/tests/canvas-ui-check.mjs
+++ b/tests/canvas-ui-check.mjs
@@ -216,6 +216,8 @@ try {
   }
   const { canvasMemberScenario } = await import("./canvas-member-scenario.mjs");
   await canvasMemberScenario({ root, act, h, useCanvasTree, GraphCanvas, event, window, makeCanvasNode, emptyCanvas, tick, mock: (handler) => { apiMock = handler; } });
+  const { canvasUploadScenario } = await import("./canvas-upload-scenario.mjs");
+  await canvasUploadScenario({ root, act, h, GraphCanvas, window, emptyCanvas, event, tick, mock: (handler) => { apiMock = handler; } });
   await act(async () => { root.unmount(); await tick(); });
 } finally {
   await rm(folder, { recursive: true, force: true }); window.close(); stop();
diff --git a/tests/canvas-upload-scenario.mjs b/tests/canvas-upload-scenario.mjs
new file mode 100644
index 0000000..faff2ca
--- /dev/null
+++ b/tests/canvas-upload-scenario.mjs
@@ -0,0 +1,61 @@
+import assert from 'node:assert/strict';
+export async function canvasUploadScenario({root,act,h,GraphCanvas,window,emptyCanvas,event,tick,mock}) {
+ const parent='cccccccc-cccc-4ccc-8ccc-cccccccccccc',assetID='dddddddd-dddd-4ddd-8ddd-dddddddddddd';
+ const asset={id:assetID,url:`https://api.foundry.entroia.com/projects/endoleap/workspaces/w/assets/${assetID}`,width:640,height:1280,bytes:4,mime_type:'image/png'};
+ let snapshot,uploads,saves,release,mode;
+ const json=(v,status=200)=>new Response(JSON.stringify(v),{status,headers:{'content-type':'application/json'}});
+ const revoked=[],originalRevoke=URL.revokeObjectURL;URL.revokeObjectURL=(url)=>{revoked.push(url);originalRevoke(url);};
+ const NativeImage=window.Image;
+ const wait=async(check,label)=>{for(let i=0;i<100;i++){if(check())return;await act(async()=>{await new Promise(r=>setTimeout(r,30));});}throw new Error('Timeout '+label);};
+ async function reset(nextMode='delayed'){
+  await act(async()=>{root.render(null);await tick();});localStorage.clear();snapshot={version:1,document:{...emptyCanvas(),schema_version:2}};uploads=[];saves=[];release=null;mode=nextMode;
+  mock(async(url,options={})=>{
+   const parts=new URL(url,'http://localhost').pathname.split('/'),suffix=parts.slice(8).join('/'),method=options.method||'GET';
+   if(parts.at(-1)==='assets'&&method==='POST'){
+    const file=options.body.get('image');uploads.push({key:options.headers['Idempotency-Key'],bytes:Buffer.from(await file.arrayBuffer()),signal:options.signal});
+    if(mode==='failed')return json({error:'forbidden'},403);
+    if(mode==='delayed')await new Promise(resolve=>{release=resolve;});
+    return json(asset,201);
+   }
+   if(suffix==='capabilities')return json({subgraphs:{member_positions:true}});
+   if(suffix==='ai/runs')return json({runs:[]});
+   if(!suffix&&method==='PATCH'){
+    assert.ok(!options.body.includes('blob:'),'Local object URLs must never be saved');assert.equal(options.headers['If-Match'],`"${snapshot.version}"`);
+    snapshot.document=JSON.parse(options.body).document;snapshot.version++;saves.push(structuredClone(snapshot.document));return json({version:snapshot.version});
+   }
+   if(!suffix)return json(snapshot);
+   throw new Error('Unhandled upload request '+url);
+  });
+  await act(async()=>{root.render(h(GraphCanvas,{board:{id:parent,workspace_id:'w',kind:'board',title:'Upload test',version:1},snapshot:structuredClone(snapshot)}));await tick();});
+ }
+ async function choose(label='添加图片'){
+  await event(document.querySelector(`[aria-label="${label}"]`),'click');
+  const input=document.querySelector('input[type="file"][accept^="image/"]');
+  Object.defineProperty(input,'files',{configurable:true,value:[new File(['test'],'local.png',{type:'image/png'})]});
+  await act(async()=>{input.dispatchEvent(new window.Event('change',{bubbles:true}));await tick();});
+  await wait(()=>uploads.length,'upload started');
+ }
+ try {
+  await reset();await choose();
+  const local=document.querySelector('.react-flow__node img[src^="blob:"]');assert.ok(local,'Selected file immediately appears on the canvas before upload acknowledgement');const localURL=local.getAttribute('src');
+  assert.ok(document.querySelector('[aria-label="图片上传状态"]'));assert.equal(snapshot.document.nodes.length,0);assert.equal(saves.length,0);assert.deepEqual(uploads[0].bytes,Buffer.from('test'));
+  await event(document.querySelector('[aria-label="添加文本卡片"]'),'click');assert.equal(document.querySelectorAll('.react-flow__node').length,2,'Other content can be added during upload');
+  await act(async()=>{release();await tick();});await wait(()=>document.querySelector('.react-flow__node img[src$="?variant=preview"]'),'managed image rendered');
+  assert.ok(document.querySelector(`img[src="${localURL}"]`),'Local image remains visible while remote preview loads');
+  const remote=document.querySelector('.react-flow__node img[src$="?variant=preview"]');await act(async()=>{remote.dispatchEvent(new window.Event('load'));await tick();});
+  assert.ok(!document.querySelector(`img[src="${localURL}"]`));assert.ok(revoked.includes(localURL));await wait(()=>snapshot.document.nodes.some(n=>n.data.src===asset.url),'original reference saved');
+  assert.equal(snapshot.document.nodes.filter(n=>n.data.src===asset.url).length,1);assert.equal(snapshot.document.nodes.find(n=>n.data.src===asset.url).data.assetId,assetID);
+  console.log('PASS uploads: immediate local preview, unrelated editing, original-byte attachment and no blob URL persistence');
+  await reset('failed');await choose();await wait(()=>document.querySelector('[aria-label="图片上传状态"]')?.textContent.includes('上传未完成'),'visible upload failure');
+  assert.ok(document.querySelector('img[src^="blob:"]'));assert.equal(saves.length,0);const key=uploads[0].key;mode='delayed';
+  await event([...document.querySelectorAll('[aria-label="图片上传状态"] button')].find(n=>n.textContent==='重试'),'click');assert.equal(uploads.length,2);assert.equal(uploads[1].key,key,'Manual retry retains the original idempotency key');
+  await act(async()=>{release();await tick();});await wait(()=>snapshot.document.nodes.length===1,'retry saves exactly one image');assert.equal(snapshot.document.nodes[0].data.src,asset.url);
+  console.log('PASS upload retry: retained file/preview, stable idempotency key and exactly one persisted node');
+  await reset('failed');await choose();await wait(()=>document.querySelector('[aria-label="图片上传状态"]')?.textContent.includes('上传未完成'),'failed cancellation');
+  const cancelledURL=document.querySelector('img[src^="blob:"]').getAttribute('src');await event([...document.querySelectorAll('[aria-label="图片上传状态"] button')].find(n=>n.textContent==='取消'),'click');assert.equal(document.querySelector('img[src^="blob:"]'),null);assert.ok(revoked.includes(cancelledURL));assert.equal(saves.length,0);
+  window.Image=class {naturalWidth=640;naturalHeight=1280;set src(_){setTimeout(()=>this.onload?.(),0);}};
+  await reset();await choose('添加纯图片');assert.equal(document.querySelector('.react-flow__node').style.width,'240px');assert.equal(document.querySelector('.react-flow__node').style.height,'480px');
+  const unmountedURL=document.querySelector('img[src^="blob:"]').getAttribute('src');await act(async()=>{root.render(null);await tick();});assert.ok(uploads[0].signal.aborted);assert.ok(revoked.includes(unmountedURL));release();await tick();assert.equal(saves.length,0);
+  console.log('PASS upload cleanup: cancellation/unmount revoke previews, abort uploads and retain plain-image aspect ratio');
+ } finally {window.Image=NativeImage;URL.revokeObjectURL=originalRevoke;await act(async()=>{root.render(null);await tick();});}
+}