gdk-pixbuf does not support netpbm pam format
Submitted by Matthias Clasen
this format appeared in netpbm at some point, and is a generalization of the pnm family of formats.
It is a raw format with a slightly different header, and supports B/W, grayscale, rgb, all with and without alpha.
It is probably not very important, but might be a nice excercise for a rainy day to make io-pnm.c support this.
Version: git master