ImageJ - and Other Health Care
RealWorld Paint - RealWorld Paint is an free portable image/photo/animation editor.
Icy - Icy is an open community platform for bioimage informatics
miniPaint - Online graphics editing tool use HTML5 technologies like Canvas, Offline support, Drag and Drop.
Fiji - Fiji: A batteries-included distribution of ImageJ.
JugiPaint - JugiPaint is a painting software with diverse tools for various types of illustration work.