Paintbrush for Mac is a nice graphics program just like
mspaint on Windows.
Paint does this in a 2.7MB download. I’ve been dying to have a lightweight image program for my Mac (OS X Leopard). I’ve tried Seashore and GIMP but they are too heavy duty for my needs. All I want to do is take a screenshot and circle some stuff. Paint accomplishes this.
Paintbrush on Apple.com