G'MIC is a full-featured open-source framework for image processing, distributed
under the CeCILL free software licenses (LGPL-like and/or GPL-compatible). It
provides several different user interfaces to convert / manipulate / filter /
visualize generic image datasets, ranging from 1d scalar signals to 3d+t
sequences of multi-spectral volumetric images, hence including 2d color images.

WWW: https://gmic.eu/