As awesome as it is, it's pretty simple. He was refferring to my description of how to do it.
The best thing to use((what I used)) is a webcam. If you want good quality use a digi-camera but keep it still. You can complete the image without having identical photos, but it takes a bit more precision. Actually, all you'd have to do is make a bigger canvas and align the images accordingly. Then erase anything overlapping on of the characters. If one is closer to the camera than the other, keep it the top layer.
Those look real nice, keep up the work and good luck to whoever tries it.