Cover art and The Books themselves rarely sync up from a marketing standpoint.
Butcher said that his Publisher thought that Black Fedora, screamed P.I. louder than anything else they could have done.
And based on the few panels I saw at DragonCon this year, the Companies could care less if the images on the covers match up to what's in the books, as long as those images continue to sell the books to walk-ins and new readers. They say that once you're hooked and like the stories, they don't care about marketing to you anymore since you're likely to buy regardless of a cover in most instances. LOL.