This is a completely static .jpg image. But it moves. Can anyone give me a logical, science-based explanation???

My desktop background is one of those 3d sterogram images.
I have a bunch of "Magic Eye" books that I got when I was in elementary school. I used to be obsessed with these things!
The colors aren't as nice now that I saved it as a jpg, but the illusion still works. Dont cross your eyes for this one.... look past it. If you cross your eyes you'll see the image the wrong way... moving away from you.. if you do it the right way ("looking past" the image) it will pop out toward you.
Oh, and when you become a pro like me, you can even do it with the thumbnail.![]()
My desktop background is one of those 3d sterogram images.