diff --git a/api/controllers/files/image_preview.py b/api/controllers/files/image_preview.py
index 04db1c67cb..a91e745f80 100644
--- a/api/controllers/files/image_preview.py
+++ b/api/controllers/files/image_preview.py
@@ -137,7 +137,7 @@ class FilePreviewApi(Resource):
         if args.as_attachment:
             encoded_filename = quote(upload_file.name)
             response.headers["Content-Disposition"] = f"attachment; filename*=UTF-8''{encoded_filename}"
-            response.headers["Content-Type"] = "application/octet-stream"
+        response.headers["Content-Type"] = "application/octet-stream"
 
         enforce_download_for_html(
             response,