diff --git a/inference.py b/inference.py
index 99370c51..3ee994a6 100755
--- a/inference.py
+++ b/inference.py
@@ -29,7 +29,7 @@ parser.add_argument('-j', '--workers', default=2, type=int, metavar='N',
                     help='number of data loading workers (default: 2)')
 parser.add_argument('-b', '--batch-size', default=256, type=int,
                     metavar='N', help='mini-batch size (default: 256)')
-parser.add_argument('--img-size', default=224, type=int,
+parser.add_argument('--img-size', default=None, type=int,
                     metavar='N', help='Input image dimension')
 parser.add_argument('--mean', type=float, nargs='+', default=None, metavar='MEAN',
                     help='Override mean pixel value of dataset')