Normal posters have to sell to you a movie you have never seen, often without showing too much so as not to spoil the surprise. I think one of the great things about these posters is that they don’t have these constraints. These are movies we know, and the artists can play with any imagery from the film and with our memories and feelings about them. Sometimes that makes for some extraordinary stuff.
Just as a bonus here is the poster for Fantastic Fest 2008.