Gimp is the most advanced and feature-rich image editor for drawing and painting that you can get out there for free.
|Powerful advanced features|
|Steep learning curve – multi window interface|
Given its origins in Linux you will find quite a few features that don’t work the Windows way. For example, I use Windows libraries and GIMP does not so I have to find my files the long way. It also defaults to a multi-windowed interface which makes it a little unusual for Windows but there is now an option to dock the tool windows within the main GIMP window.
It has a steeper learning curve, largely because it has so many features. But also the differences from Windows standards are also a factor. So if you are inexperienced at using image editing programs, then GIMP will likely be too overwhelming to start learning on. Instead try one of the more basic editors first.
Many of its photographic image editing features come from the use of plug-ins which provide access to many Photoshop 8bf filters.