diff --git a/src/components/manifest/manifestConfig.js b/src/components/manifest/manifestConfig.js
index cf5e564..d657378 100644
--- a/src/components/manifest/manifestConfig.js
+++ b/src/components/manifest/manifestConfig.js
@@ -268,12 +268,9 @@ export async function restoreAttachmentsFromApi(apiFiles = [], existingAttachmen
       if (apiFile.thumbavif) {
         try {
           if (typeof apiFile.thumbavif === 'string') {
-            if (apiFile.thumbavif.startsWith('data:')) {
-              thumbnail = apiFile.thumbavif;
-            } else {
-              const thumbBlob = base64ToBlob(apiFile.thumbavif, 'image/avif');
-              thumbnail = URL.createObjectURL(thumbBlob);
-            }
+            thumbnail = apiFile.thumbavif.startsWith('data:')
+              ? apiFile.thumbavif
+              : `data:image/avif;base64,${apiFile.thumbavif}`;
           } else if (typeof apiFile.thumbavif === 'object') {
             const rawBytes = apiFile.thumbavif.data || apiFile.thumbavif;
             if (Array.isArray(rawBytes) || rawBytes instanceof Uint8Array) {