diff --git a/src/components/game-distribution/GamePublishPage.tsx b/src/components/game-distribution/GamePublishPage.tsx
index e355a8557..af46eced9 100644
--- a/src/components/game-distribution/GamePublishPage.tsx
+++ b/src/components/game-distribution/GamePublishPage.tsx
@@ -28,7 +28,10 @@ import {
   parseGameTagsInput,
   resolveGameInputModes,
 } from './gameMetadataOptions';
-import { type GamePublishImage } from './gamePublishAssets';
+import {
+  type GamePublishImage,
+  revokeGamePublishImagePreview,
+} from './gamePublishAssets';
 import { GamePublishClientGuide } from './GamePublishClientGuide';
 import {
   clearPublishDraft,
@@ -99,6 +102,27 @@ export function GamePublishPage({
   const [screenshotImages, setScreenshotImages] = useState<GamePublishImage[]>(
     [],
   );
+  /**
+   * 卸载时释放仍挂在界面上的本地预览 blob URL。回调里拿不到最新 state，用 ref 跟踪；显式
+   * 移除/替换的那一份已由 fieldset 处理器 revoke，这里兜住卸载与线上默认值整体覆盖。
+   */
+  const coverImageRef = useRef<GamePublishImage | null>(null);
+  const screenshotImagesRef = useRef<GamePublishImage[]>([]);
+  useEffect(() => {
+    coverImageRef.current = coverImage;
+  }, [coverImage]);
+  useEffect(() => {
+    screenshotImagesRef.current = screenshotImages;
+  }, [screenshotImages]);
+  useEffect(
+    () => () => {
+      revokeGamePublishImagePreview(coverImageRef.current);
+      for (const image of screenshotImagesRef.current) {
+        revokeGamePublishImagePreview(image);
+      }
+    },
+    [],
+  );
   // 发布灰度：`checking` 期间不渲染表单，避免白名单外的作者先上传再被后端拒绝。
   const [publishGate, setPublishGate] = useState<
     'checking' | 'allowed' | 'blocked'
diff --git a/src/components/game-distribution/GameWorkMetadataEditor.tsx b/src/components/game-distribution/GameWorkMetadataEditor.tsx
index ab3de7fa9..d0b426266 100644
--- a/src/components/game-distribution/GameWorkMetadataEditor.tsx
+++ b/src/components/game-distribution/GameWorkMetadataEditor.tsx
@@ -23,7 +23,10 @@ import {
   parseGameTagsInput,
   resolveGameInputModes,
 } from './gameMetadataOptions';
-import { type GamePublishImage } from './gamePublishAssets';
+import {
+  type GamePublishImage,
+  revokeGamePublishImagePreview,
+} from './gamePublishAssets';
 import { applyVersionMediaDefaults } from './gamePublishMediaDefaults';
 import { GamePublishMediaFieldset } from './GamePublishMediaFieldset';
 import { resolvePublishMetadataError } from './gamePublishMetadata';
@@ -84,6 +87,27 @@ export function GameWorkMetadataEditor({
   const [screenshotImages, setScreenshotImages] = useState<GamePublishImage[]>(
     [],
   );
+  /**
+   * 卸载时释放仍挂在界面上的本地预览 blob URL。回调里拿不到最新 state，用 ref 跟踪；显式
+   * 移除/替换的那一份已由 fieldset 处理器 revoke，这里兜住卸载与线上默认值整体覆盖。
+   */
+  const coverImageRef = useRef<GamePublishImage | null>(null);
+  const screenshotImagesRef = useRef<GamePublishImage[]>([]);
+  useEffect(() => {
+    coverImageRef.current = coverImage;
+  }, [coverImage]);
+  useEffect(() => {
+    screenshotImagesRef.current = screenshotImages;
+  }, [screenshotImages]);
+  useEffect(
+    () => () => {
+      revokeGamePublishImagePreview(coverImageRef.current);
+      for (const image of screenshotImagesRef.current) {
+        revokeGamePublishImagePreview(image);
+      }
+    },
+    [],
+  );
   const [isLoadingMedia, setIsLoadingMedia] = useState(
     Boolean(game.latestVersion),
   );
diff --git a/src/components/game-distribution/gamePublishMediaDefaults.test.ts b/src/components/game-distribution/gamePublishMediaDefaults.test.ts
new file mode 100644
index 000000000..b3c1ed84e
--- /dev/null
+++ b/src/components/game-distribution/gamePublishMediaDefaults.test.ts
@@ -0,0 +1,61 @@
+/* @vitest-environment jsdom */
+
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import type { GameDistributionVersionDetail } from '../../../packages/shared/src/contracts/gameDistribution';
+import { type GamePublishImage } from './gamePublishAssets';
+import { applyVersionMediaDefaults } from './gamePublishMediaDefaults';
+
+function localImage(id: string, name: string): GamePublishImage {
+  return {
+    id,
+    file: new File(['image-bytes'], name, { type: 'image/png' }),
+    src: `blob:${id}`,
+    name,
+  };
+}
+
+describe('applyVersionMediaDefaults', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('用线上默认值覆盖本地选择前先释放旧 blob 预览', async () => {
+    const revokeObjectURL = vi.fn();
+    Object.defineProperty(URL, 'createObjectURL', {
+      configurable: true,
+      writable: true,
+      value: () => 'blob:unused',
+    });
+    Object.defineProperty(URL, 'revokeObjectURL', {
+      configurable: true,
+      writable: true,
+      value: revokeObjectURL,
+    });
+
+    let cover: GamePublishImage | null = localImage('local-cover', '封面.png');
+    let screenshots: GamePublishImage[] = [
+      localImage('local-shot', '截图.png'),
+    ];
+    // 线上没有可沿用的媒体：覆盖结果为空，但被替换掉的本地预览仍必须释放。
+    const detail = {
+      game: { id: 'game-1', title: '线上作品', screenshots: [] },
+      version: { frozenMetadata: null },
+    } as unknown as GameDistributionVersionDetail;
+
+    await applyVersionMediaDefaults(detail, {
+      setCover: (updater) => {
+        cover = updater(cover);
+      },
+      setScreenshots: (updater) => {
+        screenshots = updater(screenshots);
+      },
+      isCancelled: () => false,
+    });
+
+    expect(revokeObjectURL).toHaveBeenCalledWith('blob:local-cover');
+    expect(revokeObjectURL).toHaveBeenCalledWith('blob:local-shot');
+    expect(cover).toBeNull();
+    expect(screenshots).toEqual([]);
+  });
+});
diff --git a/src/components/game-distribution/gamePublishMediaDefaults.ts b/src/components/game-distribution/gamePublishMediaDefaults.ts
index 29219ab5b..1576e0c4e 100644
--- a/src/components/game-distribution/gamePublishMediaDefaults.ts
+++ b/src/components/game-distribution/gamePublishMediaDefaults.ts
@@ -3,6 +3,7 @@ import {
   createGamePublishImageId,
   type GamePublishImage,
   resolveGamePublishImagePreview,
+  revokeGamePublishImagePreview,
 } from './gamePublishAssets';
 
 type VersionMediaApplyTarget = {
@@ -46,15 +47,20 @@ export async function applyVersionMediaDefaults(
     .map((objectKey) => objectKey?.trim() ?? '')
     .filter(Boolean);
   if (apply.isCancelled()) return;
-  apply.setCover(() => (coverObjectKey ? buildCover('') : null));
-  apply.setScreenshots(() =>
-    screenshotObjectKeys.map((objectKey, index) => ({
+  // 覆盖前先释放被替换掉的本地预览 blob URL：这一步之后旧对象不再有人引用，不 revoke 就泄漏。
+  apply.setCover((current) => {
+    revokeGamePublishImagePreview(current);
+    return coverObjectKey ? buildCover('') : null;
+  });
+  apply.setScreenshots((current) => {
+    for (const image of current) revokeGamePublishImagePreview(image);
+    return screenshotObjectKeys.map((objectKey, index) => ({
       id: createGamePublishImageId(),
       objectKey,
       src: '',
       name: `截图 ${index + 1}`,
-    })),
-  );
+    }));
+  });
 
   const coverPreview = await resolveGamePublishImagePreview(
     coverObjectKey,