diff --git a/packages/client-core/src/common/services/FileThumbnailJobState.tsx b/packages/client-core/src/common/services/FileThumbnailJobState.tsx
index 96f65cb962..148bac50a5 100644
--- a/packages/client-core/src/common/services/FileThumbnailJobState.tsx
+++ b/packages/client-core/src/common/services/FileThumbnailJobState.tsx
@@ -158,6 +158,12 @@ export const FileThumbnailJobState = defineState({
         if (seenResources.has(resource.key)) continue
         seenResources.add(resource.key)
 
+        if (resource.type === 'thumbnail') {
+          //set thumbnail's thumbnail as itself
+          Engine.instance.api.service(staticResourcePath).patch(resource.id, { thumbnailKey: resource.key })
+          continue
+        }
+
         if (resource.thumbnailKey != null || !extensionCanHaveThumbnail(resource.key.split('.').pop() ?? '')) continue
 
         getMutableState(FileThumbnailJobState).merge([
diff --git a/packages/server-core/src/projects/project/project-helper.ts b/packages/server-core/src/projects/project/project-helper.ts
index fe7121309d..a40a792edd 100644
--- a/packages/server-core/src/projects/project/project-helper.ts
+++ b/packages/server-core/src/projects/project/project-helper.ts
@@ -1784,9 +1784,15 @@ export const uploadLocalProjectToProvider = async (
       const stats = await getStats(fileResult, contentType)
       const resourceInfo = resourcesJson?.[filePathRelative]
       const type = isScene ? 'scene' : getResourceType(filePathRelative, resourceInfo!)
-      const thumbnailKey =
-        resourceInfo?.thumbnailKey ?? (isScene ? key.split('.').slice(0, -1).join('.') + '.thumbnail.jpg' : undefined)
-
+      let thumbnailKey = resourceInfo?.thumbnailKey
+      if (!thumbnailKey) {
+        if (isScene) {
+          thumbnailKey = key.split('.').slice(0, -1).join('.') + '.thumbnail.jpg'
+        } else if (type === 'thumbnail') {
+          //since thumbnails are not in resource json, we need to redefine their thumbnail keys here
+          thumbnailKey = key
+        }
+      }
       if (existingKeySet.has(key)) {
         const id = existingKeySet.get(key)!
         existingKeySet.delete(key)