diff --git a/main.py b/main.py
index a079d5c..b9d5d33 100644
--- a/main.py
+++ b/main.py
@@ -235,7 +235,7 @@ if __name__ == "__main__":
         VideoEd.denoise_image_sequence (arguments.input_dir, arguments.ext, arguments.factor)
     p = videoed_parser.add_parser( "denoise-image-sequence", help="Denoise sequence of images, keeping sharp edges. This allows you to make the final fake more believable, since the neural network is not able to make a detailed skin texture, but it makes the edges quite clear. Therefore, if the whole frame is more `blurred`, then a fake will seem more believable. Especially true for scenes of the film, which are usually very clear.")
     p.add_argument('--input-dir', required=True, action=fixPathAction, dest="input_dir", help="Input file to be processed. Specify .*-extension to find first file.")
-    p.add_argument('--ext', dest="ext", default='png', help="Image format (extension) of input files.")
+    p.add_argument('--ext', dest="ext", default=None, help="Image format (extension) of input files.")
     p.add_argument('--factor', type=int, dest="factor", default=None, help="Denoise factor (1-20).")
     p.set_defaults(func=process_videoed_denoise_image_sequence)