ImageMagick 7
Library to encode and decode images in WebP format
A fast image processing library with low memory needs
Lynkeos is an astronomical webcam image processing software for OS X.
Improved JPEG encoder
Libraries and command line tools for medical image processing.
A small C library for building user interfaces with C, XML and CSS.
A Library for Interactive Modelling and Visualisation
Software for data analysis, image processing, simulations, solver.
Heterogeneous Image Processing Acceleration (HIPACC) Framework
Siril is an astronomical image processing software for Linux.