One of the blogs I read every morning is an art blog. I came in this morning after being off a week and found that he had posted this picture of an Ivory Skeleton from about 1640.

It would make the perfect cover for a horror novel. Since it is a 1640 piece of art, there might not be much in the way of copyright issues. The actual image is from Giornale Nuovo, and I think the author took the picture at the exibition. I believe it would be safe, though, to manipulate the image to make it suitable for a cover. I am thinking that both images would be derivative works of a the original statue.

Click the image to see the original large size.
Giornale Nuovo