GIMP - GIMP is a multiplatform photo manipulation tool.
incron - This program is an "inotify cron" system. It consists of a daemon and a table manipulator.
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
fcron - Fcron is a scheduler designed for Unix/Linux systems, especially usefull when your system is not up all the day long.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Anacron - Anacron is a periodic command scheduler. It executes commands at intervals specified in days.