Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
PaintTool SAI - Learn to draw in different ways.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Corel Painter - Corel Painter is media painting software.
GIMP - GIMP is a multiplatform photo manipulation tool.