support for netpbm's PAM file format
Submitted by Jörg Walter
When trying to open a PAM file (canonical extension, you guess it, .pam), gimp says it doesn't recognize the file format. It would be nice to have support for it, as PAM is as easy to create as PPM & friends, and includes support for arbitrary color channels, especially you can do RGBA. Very useful when you want to do debugging dumps of intermediate results of image processing - PPM is not enough, it doesn't have alpha. Spec is at http://netpbm.sourceforge.net/doc//pam.html, it's works mostly like PPM, just the header data is a little bit different.