MyPaint is an open source paint application for creating excellent works of art in various operating platforms including Windows, Linux and OSX. It comes with a distraction-free workspace packaged with a wide variety of brushes that allow users to paint their imagination on the limit-less canvas. One can keep working without the need to resize the canvas.
This painting tool can be used with a mouse as well as a pressure-sensitive tablet. So its ideal for both the professional artist as well as those who just want to have some fun.