add thumbnail preview for each queued image.

Create and revoke blob URLs on pick and session reset; reset upload session on view unmount.

frontend/src/components/upload/UploadQueueList.vue

@@ -7,6 +7,18 @@
                 :class="isRowSelected(row) ? 'bg-muted/80' : ''"
                 @click="emit('select', row.file)"
             >
+                <img
+                    v-if="row.thumbnailUrl"
+                    :src="row.thumbnailUrl"
+                    class="h-10 w-10 shrink-0 rounded border border-border object-cover"
+                    loading="lazy"
+                    decoding="async"
+                />
+                <span
+                    v-else
+                    class="h-10 w-10 shrink-0 rounded border border-border bg-muted/60"
+                    aria-hidden="true"
+                />
                 <span class="min-w-0 flex-1 truncate text-sm font-medium">{{ row.file.name }}</span>
                 <span class="shrink-0 text-xs text-muted-foreground">
                     {{ prettyBytes(row.file.size, { maximumFractionDigits: 1 }) }}

frontend/src/types/upload/UploadQueueRow.ts

@@ -4,6 +4,7 @@ import type { UploadQueueEntry } from '@/types/upload/UploadQueueEntry';
 export type UploadQueueRow = {
     file: File;
     key: string;
+    thumbnailUrl: string | null;
     metadata: MetadataPreviewEntry;
     upload: UploadQueueEntry;
 };

frontend/src/utils/upload/createQueueThumbnailUrls.spec.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it, vi, beforeEach, afterEach } from 'vitest';
+import { createQueueThumbnailUrls } from '@/utils/upload/createQueueThumbnailUrls';
+
+const makeFile = (name: string, size: number, lastModified: number): File =>
+    new File([new Uint8Array(size)], name, { type: 'image/png', lastModified });
+
+describe('createQueueThumbnailUrls', () => {
+    beforeEach(() => {
+        vi.stubGlobal(
+            'URL',
+            Object.assign(globalThis.URL, {
+                createObjectURL: vi.fn(() => 'blob:mock-1')
+            })
+        );
+    });
+
+    afterEach(() => {
+        vi.unstubAllGlobals();
+    });
+
+    it('creates one object URL per file', () => {
+        const files = [makeFile('a.png', 10, 1), makeFile('b.png', 20, 2)];
+
+        const urlsByKey = createQueueThumbnailUrls(files);
+
+        expect(URL.createObjectURL).toHaveBeenCalledTimes(2);
+        expect(Object.keys(urlsByKey)).toHaveLength(2);
+    });
+});

frontend/src/utils/upload/createQueueThumbnailUrls.ts

@@ -0,0 +1,11 @@
+import { makeKeyFromFile } from '@/utils/file/makeKeyFromFile';
+
+export const createQueueThumbnailUrls = (files: File[]): Record<string, string> => {
+    const urlsByKey: Record<string, string> = {};
+
+    for (const file of files) {
+        urlsByKey[makeKeyFromFile(file)] = URL.createObjectURL(file);
+    }
+
+    return urlsByKey;
+};

frontend/src/utils/upload/revokeQueueThumbnailUrls.spec.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it, vi } from 'vitest';
+import { revokeQueueThumbnailUrls } from '@/utils/upload/revokeQueueThumbnailUrls';
+
+describe('revokeQueueThumbnailUrls', () => {
+    it('revokes every URL in the map', () => {
+        vi.stubGlobal(
+            'URL',
+            Object.assign(globalThis.URL, {
+                revokeObjectURL: vi.fn()
+            })
+        );
+
+        revokeQueueThumbnailUrls({ a: 'blob:1', b: 'blob:2' });
+
+        expect(URL.revokeObjectURL).toHaveBeenCalledWith('blob:1');
+        expect(URL.revokeObjectURL).toHaveBeenCalledWith('blob:2');
+
+        vi.unstubAllGlobals();
+    });
+});

frontend/src/utils/upload/revokeQueueThumbnailUrls.ts

@@ -0,0 +1,5 @@
+export const revokeQueueThumbnailUrls = (urlsByKey: Record<string, string>): void => {
+    for (const url of Object.values(urlsByKey)) {
+        URL.revokeObjectURL(url);
+    }
+};

frontend/src/views/UploadView.vue

@@ -28,7 +28,7 @@
 </template>
 
 <script setup lang="ts">
-import { computed, onBeforeMount, ref } from 'vue';
+import { computed, onBeforeMount, onBeforeUnmount, ref } from 'vue';
 import type UploadIntakeControls from '@/components/upload/UploadIntakeControls.vue';
 import { config } from '@/config';
 import { useExiftoolStore } from '@/stores/exiftool';
@@ -39,6 +39,8 @@ import { makeKeyFromFile } from '@/utils/file/makeKeyFromFile';
 import { analyzePickedUploadFiles } from '@/utils/upload/analyzePickedUploadFiles';
 import { buildPickedUploadWarning } from '@/utils/upload/buildPickedUploadWarning';
 import { formatUploadBatchSettingsSummary } from '@/utils/upload/formatUploadBatchSettingsSummary';
+import { createQueueThumbnailUrls } from '@/utils/upload/createQueueThumbnailUrls';
+import { revokeQueueThumbnailUrls } from '@/utils/upload/revokeQueueThumbnailUrls';
 import prettyBytes from 'pretty-bytes';
 
 const { maxQueueSize, maxImageBytes } = config.validation.upload;
@@ -67,6 +69,7 @@ const batchSettings = ref<UploadBatchSettingsForm>({
 const uploadConfirmed = ref(false);
 const showShareLinks = ref(false);
 const confirmedBatchSummary = ref<string | null>(null);
+const thumbnailUrlsByKey = ref<Record<string, string>>({});
 
 onBeforeMount(async () => {
     try {
@@ -76,6 +79,10 @@ onBeforeMount(async () => {
     }
 });
 
+onBeforeUnmount(() => {
+    resetUploadSession();
+});
+
 const maxImageSizeFormatted = computed(() => prettyBytes(maxImageBytes, { binary: true, maximumFractionDigits: 1 }));
 
 const queueRows = computed(() =>
@@ -85,6 +92,7 @@ const queueRows = computed(() =>
         return {
             file,
             key,
+            thumbnailUrl: thumbnailUrlsByKey.value[key] ?? null,
             metadata: metadataStore.getPreview(file),
             upload: uploadStore.getUpload(file)
         };
@@ -136,6 +144,7 @@ const onFilesPicked = async (picked: File[]): Promise<void> => {
     );
 
     queuedFiles.value = accepted;
+    thumbnailUrlsByKey.value = createQueueThumbnailUrls(accepted);
     selectedFile.value = accepted[0] ?? null;
 
     loadingMetadata.value = true;
@@ -148,9 +157,10 @@ const onFilesPicked = async (picked: File[]): Promise<void> => {
         loadingMetadata.value = false;
     }
 };
-
 const resetUploadSession = (): void => {
     selectionError.value = null;
+    revokeQueueThumbnailUrls(thumbnailUrlsByKey.value);
+    thumbnailUrlsByKey.value = {};
     clearAllPreviews();
     queuedFiles.value = [];
     selectedFile.value = null;