Convert a Windows ICO file to a PAM file. More information: https://netpbm.sourceforge.net/doc/winicontopam.html.
winicontopam path/to/input_file.ico > path/to/output.pam
winicontopam -allimages path/to/input_file.ico > path/to/output.pam
winicontopam -image n path/to/input_file.ico > path/to/output.pam
winicontopam -andmasks path/to/input_file.ico > path/to/output.pam