I’ve been looking at some free painting programs. In particular I wanted something that had realistic natural-painting tools (oil, watercolour, crayon, pencil, airbrush, pastels) to use with my graphics tablet.
Some of these have those tools and others don’t. But all of them are rather good in some way or another.
Deep Paint: some interesting and unusual natural and special-effect painting tools in this one. It says something about registering but I don’t think you have to anymore.
ArtWeaver: you can’t complain at something like this for free. In terms of overall features it’s like a slightly cut-down version of Photoshop (it has a similar layers system), but with lots of natural-texture painting tools.
Pixia: the English version of some Japanese painting software. I found the layers system in this a bit confusing, but it’s worth a look. The beauty of all of these programs is that they are relatively small and dead easy to uninstall if you don’t like them.
PhotoFiltre: if you want something that’s simple and fast for basic painting, then this could be for you.
The Gimp: one of the best-known free paint programs. Available for Windows and Linux.