miniPaint - Online graphics editing tool use HTML5 technologies like Canvas, Offline support, Drag and Drop.
GIMP - GIMP is a multiplatform photo manipulation tool.
RealWorld Paint - RealWorld Paint is an free portable image/photo/animation editor.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
JugiPaint - JugiPaint is a painting software with diverse tools for various types of illustration work.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.