This is rather disgusting. This image was created, as Lumos mentioned, by our own Dumbledore! The image has been circulated as a "first look" at Cuaron's dementors, when it is, in fact, an image created using Photoshop!

Dumbledore has no objections to having his image posted, but he would like credit for his work, and wants to make sure that it is not masqueraded as a first look at the dementors in the movie.