2 Display details about the image file.
5 Convert frames to another image format.
8 Display additional information on standard output.
11 Read image data from FILE instead of standard input.
14 When decoding, set the output format to FMT. One of png,
18 When decoding, output filenames will begin with NAME
22 Instead of performing palette lookups, the palette index
23 values for each pixel are used directly as grayscale level.
26 Load FILE as the base image palette.
29 Load FILE as the override palette.
32 Print a version message and then exit.
35 Print a help message and then exit.