Drawing, graphics conversion, software development, administration.
Easy-to-use command line tool for images
Swiss army knife of image processing
Various small and useful command-line utilities
Open Source Solid Modeling CAD
Convert images to Ascii Art, with a lot of options and drawing tools
Merge image files into a single Windows icon (.ico) file.
Convert jpeg(exif/jfif)/mpo/jps image to/from xml
Converts AtariST images (.neo, .pi1, .pi2, .pi3) to gifs (using gd).