Easy to do - travertine tile + photo printed on tissue paper - they have made these into coasters but they would be nice on the wall - I would leave a slightly wider edge - you could also experiment with making photo transfers directly on the tile
SO DOING THIS FOR GIFTS!!! This is the best tutorial I've yet found for that whole DIY photo canvas that people are into doing. So easy to follow, and encouraging. Takes just minutes. Imagine the gifts you can make for family and friends!