diff --git a/data/model/legacy.py b/data/model/legacy.py
index b4601782e..2cd8be94b 100644
--- a/data/model/legacy.py
+++ b/data/model/legacy.py
@@ -83,6 +83,10 @@ class InvalidBuildTriggerException(DataModelException):
   pass
 
 
+class InvalidImageException(DataModelException):
+  pass
+
+
 class TooManyUsersException(DataModelException):
   pass
 
@@ -1180,6 +1184,23 @@ def find_create_or_link_image(docker_image_id, repository, username, translation
     return new_image
 
 
+def get_storage_by_uuid(storage_uuid):
+  placements = list(ImageStoragePlacement
+    .select(ImageStoragePlacement, ImageStorage, ImageStorageLocation)
+    .join(ImageStorageLocation)
+    .switch(ImageStoragePlacement)
+    .join(ImageStorage)
+    .where(ImageStorage.uuid == storage_uuid))
+
+  if not placements:
+    raise InvalidImageException('No storage found with uuid: %s', storage_uuid)
+
+  found = placements[0].storage
+  found.locations = {placement.location.name for placement in placements}
+
+  return found
+
+
 def set_image_size(docker_image_id, namespace_name, repository_name,
                    image_size):
   try:
diff --git a/tools/uncompressedsize.py b/tools/uncompressedsize.py
index 530ba3836..32ba0957c 100644
--- a/tools/uncompressedsize.py
+++ b/tools/uncompressedsize.py
@@ -1,31 +1,54 @@
+import json
+import logging
+
 from data import model
 from data.database import ImageStorage
 from app import app, storage as store
+from data.database import db
+
+
+logger = logging.getLogger(__name__)
 
-import logging
 
 def backfill_sizes():
-  count = ImageStorage.select().where(ImageStorage.uncompressed_size == None).count()
-  counter = 0
-  for image_storage in ImageStorage.select().where(ImageStorage.uncompressed_size == None):
-    logging.debug("Backfilling uncompressed size: %s of %s" % (counter, count))
+  query = (ImageStorage
+           .select()
+           .where(ImageStorage.uncompressed_size == None, ImageStorage.uploading == False)
+           .limit(100))
 
-    # Lookup the JSON for the image.
-    uuid = image_storage.uuid
-    with_locations = model.get_storage_by_uuid(uuid)
+  total = 0
+  missing = 0
+  batch_processed = 1
 
-    json_data = store.get_content(with_locations.locations, store.image_json_path(uuid))
-    size = json_data.get('Size', None)
-    if size is None:
-      continue
+  while batch_processed > 0:
+    batch_processed = 0
+    with app.config['DB_TRANSACTION_FACTORY'](db):
+      for image_storage in query.clone():
+        total += 1
+        batch_processed += 1
 
-    image_storage.uncompressed_size = size
-    image_storage.save()
-    counter += 1
+        if (total - 1) % 100 == 0:
+          logger.debug('Storing entry: %s', total)
+
+        # Lookup the JSON for the image.
+        uuid = image_storage.uuid
+        with_locations = model.get_storage_by_uuid(uuid)
+
+        json_string = store.get_content(with_locations.locations, store.image_json_path(uuid))
+        json_data = json.loads(json_string)
+        size = json_data.get('Size', json_data.get('size', -1))
+
+        if size == -1:
+          missing += 1
+
+          logger.debug('Missing entry %s (%s/%s)', uuid, missing, total)
+
+        image_storage.uncompressed_size = size
+        image_storage.save()
 
 
 if __name__ == "__main__":
   logging.basicConfig(level=logging.DEBUG)
   logging.getLogger('boto').setLevel(logging.CRITICAL)
 
-  backfill_sizes()
\ No newline at end of file
+  backfill_sizes()