The amazing image shown in the link below is an unreal photomosaic, which is a picture composed of other, smaller, pictures.

When viewed from a distance, a photomosaic appears like any other painting or photo, but upon closer inspection, the individual photos can be seen.

But this photomosaic is unlike any other you've seen before. Seemingly, every crevice of the man's face appears smooth and unpixelated (unlike the accompanying photo), but click on a spot on the photo and it takes you to an unending set of tiny photos that are made up of even tinier photos. Forever.

To learn how to make your own photomosaics (with free software), you'll want to read this interesting Engadget piece.