I found a technique for decorating cakes a few years ago I really like. Start with a picture you want to use. Open it up in an image editor, I use Gimp, and convert it to two or three tones (I’ll add instructions later, but you can find a tutorial online). Reverse the image and print it off, making sure the size is approximately right.
Now the fun part. I tape the image on the back of a cookie tray, then cover the whole thing with plastic wrap making sure it’s pulled tight and secured in place (more tape). Then I use melted chocolate (white, dark and a mixture of the two) to trace the image. I put the chocolate in a sandwich bag and snip off a little bit of one corner to make a poor icing kit. You wouldn’t want to use a real one, it would be a nightmare to clean up.
The back side that you’re working on will end up looking terrible, but the side that is down against the cookie tray will come out, well, like the pictures above. The best part is, unlike fondant, people actually want to eat chocolate.