KolourPaint is a free, easy-to-use paint program for KDE.

It aims to be conceptually simple to understand; providing a level of
functionality targeted towards the average user. It's designed for
daily tasks like:
* painting - drawing diagrams and "finger painting";
* image manipulation - editing screenshots and photos, applying effects;
* icon editing - drawing clipart and logos with transparency.

It's not an unusable and monolithic program where simple tasks like
drawing lines become nearly impossible. Nor is it so simple that it
lacks essential features like undo/redo.