Motion - Failed to read mask image

[tqchiem]

I created all white mask file (e.g., mask01.pgm) and entered its pathname in the configuration file:

mask_file /etc/motion/mask01.pgm

The mask is in 640x480 matching with the camera low resolution (netcam_url). After restarting Motion, I get the following error in the motion log:

[2:ml2:Camera_001] [ERR] [ALL] [Jul 31 15:58:12] get_pgm: Failed reading maximum value in pgm file: Success
[2:ml2:Camera_001] [ERR] [ALL] [Jul 31 15:58:12] motion_init: Failed to read mask image. Mask feature disabled.

Motion does detect motion in the view. I then created a new mask with a black area just to test. Motion has the same error and simply ignores mask (as it says).

What is causing this problem and how do I correct it?.

Any help would be very much appreciated. Thank you.

[tqchiem]

It was discovered that my photo editor does not have an explicit option to save the mask file in binary format. I used a different editor with binary save option and it works.