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.
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
GIMP - GIMP is a multiplatform photo manipulation tool.