NiceDraw (iPad version)
(There is also a N900 version)
NiceDraw lets less experienced artists use a photo as template for their own drawings.
The unique feature is the slider, which allows you to change the brightness of the template quickly, to achieve a good visibility of template and your own drawing.
The slider is always accessible, as the brightness is often changed during drawing.
You will be surprised how nice your own drawings will be.
Keywords: paint, draw, sketch
Change the brightness and zoom to fit your needs:
Ready within 5 min:
You may have a look at a 2:24 min video (done with a previous version without orientation support).