darktable is an open source photography workflow application
Swiss army knife of image processing
A collection of packages providing extra functionality for GNU Octave
ProStack - a platform for image processing and analysis
Graphic Live Mixer
A small C library for building user interfaces with C, XML and CSS.
Advanced image processing toolbox for Scilab on Unix/Linux/Mac OS
Video Capture from Windows WDM cameras
Software for data analysis, image processing, simulations, solver.
Siril is an astronomical image processing software for Linux.