I've been messing around with photo transfers using mod podge. Very simply, you print your picture from your printer on normal paper, mod podge all over image side and then lay flat on surface. I used cheap canvases here from The Works. Make sure you get all bubbles and creases out, otherwise those bits won't transfer. Leave to dry, then rub the paper off with a wet sponge.
The images are not as clear as original images. But this was very EASY and very CHEAP. The kids were impressed so I'll let them do some. You can see bits that I could rub a bit more paper off of. But maybe these would be great if you wanted the image as a base to paint over, add extra layers over.