[storybook] Add placeholder image to storybook (#11874)

GitOrigin-RevId: 8d6e6d3ba1aec223de698edc2613ed0b061d1e43

services/web/frontend/stories/decorators/scope.tsx

@@ -98,7 +98,13 @@ const initialize = () => {
       findEntityByPath: () => null,
       getEntityPath: () => null,
       getRootDocDirname: () => undefined,
-      getPreviewByPath: () => null,
+      getPreviewByPath: (path: string) =>
+        path === 'frog.jpg'
+          ? {
+              extension: 'png',
+              url: 'data:image/png;base64,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',
+            }
+          : null,
     },
     editorManager: {
       getCurrentDocId: () => 'foo',