RawTherapee is a cross-platform raw image processing program, released under the GNU General Public License Version 3.

XnConvert is a powerful and free cross-platform batch image processor, allowing you to combine over 80 actions.

GraphicsMagick is a utility of image processing.

Nomacs is a free, open source image viewer, which supports multiple platforms.

Phatch (PHoto & bATCH) is a raster graphics editor used to batch process digital graphics and photographs. Phatch can be used on the desktop as a GUI program …