What do you call pictures where it's a mountain or a tree and you can see a face

Question:

What do you call pictures where it's a mountain or a tree and you can see a face or a body in it?

I had once seen a CD cover with a picture of a tree and the branches made out a face of a man. And I was just wondering what you would call them and where I could find some pictures.

Best Answer - Chosen by Asker: According to Wikipedia, pareidolia is "a psychological phenomenon involving a vague and random stimulus (usually an image) being mistakenly perceived as recognizable."
One common form of pareidolia is seeing faces in objects (like the flying spaghetti monster on a tortilla, or the face of Sean Hannity on a human being). There is an excellent book filled with pictures of faces on objects, called Faces.

My friend Jim Leftwich has been taking his own pictures of faces for a while, and has a flickr gallery with them. As I expect from Jim, the photos are whimsical and surprising.