Microsoft Paint has been the basic image editor built into Windows since, well, for a long time. It has had a few minor updates, but has never really been a usable program other than simple stick figures or shapes. Now, Microsoft is working on Project Gustav, an image painting program that mimics a paint brush and canvas. I think it looks amazing!
Typically the experience of painting on a computer is nothing like painting in the real world. Real painting is actually a very complex phenomenon