diff --git a/server/src/middleware/upload.ts b/server/src/middleware/upload.ts
index 3d1d1b1..c3c9171 100644
--- a/server/src/middleware/upload.ts
+++ b/server/src/middleware/upload.ts
@@ -18,7 +18,7 @@ const storage = multer.diskStorage({
 });
 
 const ALLOWED_MIMES = [
-  'image/jpeg', 'image/png', 'image/webp', 'image/heic',
+  'image/jpeg', 'image/png', 'image/webp', 'image/heic', 'image/avif',
   'application/pdf',
 ];
 
diff --git a/server/src/resize.ts b/server/src/resize.ts
index db9d7db..a7370bf 100644
--- a/server/src/resize.ts
+++ b/server/src/resize.ts
@@ -14,7 +14,7 @@ const VARIANTS: VariantSpec[] = [
 ];
 
 const RESIZABLE_MIMES = new Set([
-  'image/jpeg', 'image/png', 'image/webp', 'image/heic',
+  'image/jpeg', 'image/png', 'image/webp', 'image/heic', 'image/avif',
 ]);
 
 export function isResizable(mimeType: string): boolean {