CinePaint is a collection of free, open source applications built for image processing and deep paint manipulation. CinePaint is used for motion picture frame-by-frame retouching, dirt removal, wire rig removal, render repair, background plates, and 3d model textures.
It's been used on many feature films, including The Last Samurai where it was used to add flying arrows. It's also being used by pro photographers who need greater color fidelity than is available in other tools.
CinePaint is fundamentally different from other painting tools because it handles high fidelity image formats such as Kodak Cineon, SMPTE DPX, and ILM-NVIDIA OpenEXR. To do that properly requires a 32-bit per channel color engine core so that data isn't crushed into 8-bit color channels.
The CinePaint core is 8-bit, 16-bit, and 32-bit as needed. It's different from GraphicsMagick which also supports different color depths but only as a compile-time switch. (GraphicsMagick has better support for film industry file formats than ImageMagick.)
XnView Full is a powerful tool that enables users to view, process, and convert image files easily. XnView Full has all plug-ins and languages included. XnView Standard has just a few add-ons included.