MyPaint is a fast and easy open-source graphics application for digital painters. It lets you focus on the art instead of the program. You work on your canvas with minimum distractions, bringing up the interface only when you need it.

exists for several platforms

supports pressure sensitive graphics tablets

extensive brush creation and configuration options

unlimited canvas (you never have to resize)

basic layer support

MyPaint comes with a large brush collection including charcoal and ink to emulate real media, but the highly configurable brush engine allows you to experiment with your own brushes and with not-quite-natural painting. Before beginning it is a good idea to read the quick-start tutorial to see how the program is meant to be used.