PhotoSketch is an “Internet Image Montage” project from five students at Tsinghua University and the National University of Singapore. The basic premise, which they present in the form of a research paper [pdf], works like this:

• Draw the outlines of the figures you want in your picture – anything from seagulls to a wedding kiss;
• Add labels for each of the items, as well as for the background.
• PhotoSketch will then find real-life images to match your doodles and put them together in a Photoshopped image that will make your jaw drop.

And before you say "it must be fake", download and read the research paper (in pdf), already evaluated by the scientific community.