You currently cannot copyright their direct output but you can copyright the product you make with it.
A pure AI image isn't copyrightable, but modifying it to a point or making a comic book out of those images is okay.
Personally I'm looking forward to the Indy scene that will come with these tools more than how Hollywood uses it. Hollywood is already dead, they just don't realize it.
Somebody actually made a comic book with AI images and the copyright got rejected on the art (held up on the words though). So maybe if you modify the images quite a bit, but not if you just put them in comic book form.