diff --git a/src/features/subject-images/SubjectImagesPage.vue b/src/features/subject-images/SubjectImagesPage.vue
index 54d80d5..40a9597 100644
--- a/src/features/subject-images/SubjectImagesPage.vue
+++ b/src/features/subject-images/SubjectImagesPage.vue
@@ -700,6 +700,7 @@ const rules = { concurrency: integerRule('批量并发'), limit: integerRule('
                     <AssetImage
                         :src="coverImage(form)?.imageUrl"
                         :alt="`${form.subject.name} · ${form.name}`"
+                        :class="{ 'form-image-has-source': Boolean(coverImage(form)?.imageUrl) }"
                         :object-fit="layout === 'masonry' ? 'contain' : 'cover'"
                         preview
                         :empty-text="hasRunningImages(form.images) ? '后台正在生成图片' : '尚未生成图片'"
@@ -844,10 +845,13 @@ const rules = { concurrency: integerRule('批量并发'), limit: integerRule('
     grid-row-end: span var(--form-image-row-span, 1);
 }
 .form-image-masonry .asset-image {
+    aspect-ratio: 1 / 1;
+}
+.form-image-masonry .asset-image.form-image-has-source {
     @apply aspect-auto;
 }
-.form-image-masonry .asset-image .n-image,
-.form-image-masonry .asset-image .n-image img {
+.form-image-masonry .asset-image.form-image-has-source .n-image,
+.form-image-masonry .asset-image.form-image-has-source .n-image img {
     @apply h-auto;
 }
 .gallery-sticky-controls > .form-image-filter-region {
diff --git a/tests/components/ui/flatTheme.test.ts b/tests/components/ui/flatTheme.test.ts
index 32743f7..26e999f 100644
--- a/tests/components/ui/flatTheme.test.ts
+++ b/tests/components/ui/flatTheme.test.ts
@@ -177,9 +177,10 @@ describe('全站平面主题', () => {
         expect(css).toMatch(
             /\.form-image-masonry > \.form-image-card\s*\{[^}]*grid-column-start:\s*var\(--form-image-column,\s*auto\);[^}]*grid-row-start:\s*var\(--form-image-row-start,\s*auto\);[^}]*grid-row-end:\s*span var\(--form-image-row-span,\s*1\);/
         )
-        expect(css).toMatch(/\.form-image-masonry \.asset-image\s*\{[^}]*aspect-ratio:\s*auto;/)
+        expect(css).toMatch(/\.form-image-masonry \.asset-image\s*\{[^}]*aspect-ratio:\s*1 \/ 1;/)
+        expect(css).toMatch(/\.form-image-masonry \.asset-image\.form-image-has-source\s*\{[^}]*aspect-ratio:\s*auto;/)
         expect(css).toMatch(
-            /\.form-image-masonry \.asset-image \.n-image,\s*\.form-image-masonry \.asset-image \.n-image img\s*\{[^}]*height:\s*auto;/
+            /\.form-image-masonry \.asset-image\.form-image-has-source \.n-image,\s*\.form-image-masonry \.asset-image\.form-image-has-source \.n-image img\s*\{[^}]*height:\s*auto;/
         )
     })