1. Pick a spot on the picture (the middle seems to work
best) and just stare at it.
2. Allow your eyes to relax, don't just stare AT the
image, stare THROUGH it. You'll notice your eyes go slightly out of
focus.
3. Believe that an image is behind the graphic you can
see, THINK about it.
4. Keep staring, don't give up, once you begin to see the
first image, it gets much easier.