Reads a Microsoft Windows .ico file, converts it to one or more ppms.
A Windows icon contains 1 or more images, at different resolutions and color depths. Each image has an 'and' mask, which contains transparancy data.
By default, the output goes to Standard Output. If you specify ppmdestfile, output goes into one or more files named as follows. If it's just one file (i.e. you specify the -multippm option or don't specify -allicons), the file specification is ppmdestfile.ppm. If it's multiple files, their file specifications are ppmdestfile_1.ppm, ppmdestfile_2.ppm, etc.
For each icon written, also write the 'and' (transparancy) mask as a seperate PBM file. It's name is of the form ppmdestfile_and.pbm or ppmdestfile_and_1.pbm.
Extract all images from the .ico file.
Extract only the best quality (largest, then highest bpp) image from the .ico file.