ArtRage has the ability to load a photograph as a tracing paper, overlaid on your canvas as you work. As you start a stroke, ArtRage can choose the colour from the tracing paper. So even if you just do lots of random splots of paint, you'll end up with a painted (quite impressionistic) version of your photograph.
But you can do better than that by following the contours and edges with your brush to make it less random.
If people who can't paint at all (me, for example!) can produce great results by using the tracing feature.
Try the Starter edition of ArtRage 2.5 It's free for download and use, and it has the tracing feature.
You can download the Starter edition of ArtRage from here:
AndyRage's mantra for graphics engine code:
"Sure - how hard can it be?"