Note: help and version output are generated by a naïve script which tries a few variants of
<command> --help, <command> -h etc. to find the command's help and version info.
Sometimes it gets lucky, sometimes it doesn't; if the output below looks wrong, it probably is.
gmerlin_psnr -V (return code: 255)
Usage: gmerlin_psnr <image1> <image2>
gmerlin_psnr --help (return code: 255)
Usage: gmerlin_psnr <image1> <image2>