diff --git a/endpoints/registry.py b/endpoints/registry.py
index b2018a2b0..8af9fcb03 100644
--- a/endpoints/registry.py
+++ b/endpoints/registry.py
@@ -307,7 +307,7 @@ def get_image_json(namespace, repository, image_id, headers):
 
   profile.debug('Looking up repo layer size')
   try:
-    size = repo_image.image_size or repo_image.storage.image_size
+    size = (repo_image.storage and repo_image.storage.image_size) or repo_image.image_size
     headers['X-Docker-Size'] = str(size)
   except OSError:
     pass