diff --git a/sky/task.py b/sky/task.py
index f623be6a548..f6652d9e1c7 100644
--- a/sky/task.py
+++ b/sky/task.py
@@ -147,6 +147,8 @@ def _add_docker_login_config(resources: 'resources_lib.Resources'):
         # Already checked in extract_docker_image
         assert len(resources.image_id) == 1
         region = list(resources.image_id.keys())[0]
+        # We automatically add the server prefix to the image name if
+        # the user did not add it.
         server_prefix = f'{docker_login_config.server}/'
         if not docker_image.startswith(server_prefix):
             docker_image = f'{server_prefix}{docker_image}'