G'MIC is an open and full-featured framework for image processing, providing several different user interfaces to convert/manipulate/filter/visualize generic image datasets, from 1d scalar signals to 3d+t sequences of multi-spectral volumetric images.
- A portable and thread-safe C++ library 'libgmic' for generic image processing, embeddable in third-party applications.
- A command line interface 'gmic' to perform image processing operations from a shell.
- An easy-to-use plug-in 'gmic_gimp' which adds hundred of new filters to GIMP.
- A web-service 'G'MIC Online', to apply image fiters directly on a web-browser.
- A Qt-based interface 'ZArt' for real-time manipulation of webcam images.
- A complete script language to develop your own complex image processing pipelines.
I really enjoy using G'MIC and use it's features inside of Gimp before using any other plug-in's features. I often restore old scanned film photographs, negatives, and slides and its capabilities keep me confident in being able to restore even the most challenging materials. I scored it a 4 on support only because I haven't ever needed to use their support and can't really rate it.