Drawing, graphics conversion, software development, administration.
Swiss army knife of image processing
Various small and useful command-line utilities
Open Source Solid Modeling CAD
Complete solution for HDR photography
angif fork with transparency layers (proof of concept implementation)
Convert jpeg(exif/jfif)/mpo/jps image to/from xml
Converts AtariST images (.neo, .pi1, .pi2, .pi3) to gifs (using gd).