ok i was sent something like this via email and thought i would try it with a bocking picture, which i found depending on the size of the subject worked pretty well.
heres what you do..
Look at the center of the photo while crossing your eyes until you see three images. Concentrate on the middle image until it comes into crisp focus and the 3D image will appear real enough to touch (even when you shift your head left to right).
heres an example bocking pic, but its literally just the same image side by side, nothing else.
the image is best viewed quite big so it might be better to save it to desktop if its resized.