diff --git a/novaclient/v1_1/shell.py b/novaclient/v1_1/shell.py
index 2952c604f..1463f5fd4 100644
--- a/novaclient/v1_1/shell.py
+++ b/novaclient/v1_1/shell.py
@@ -1283,7 +1283,8 @@ def do_image_delete(cs, args):
     dest='tenant',
     metavar='<tenant>',
     nargs='?',
-    help=_('Display information from single tenant (Admin only).'))
+    help=_('Display information from single tenant (Admin only). '
+           'The --all-tenants option must also be provided.'))
 @cliutils.arg(
     '--user',
     dest='user',