In a series on book covers that is running on Mad Genius Club, Sarah Hoyt explains some of the challenges in designing an alternate history book cover. One of the examples she uses is “Operation Flash”.
I have, btw, recently done this cover for Nitay, who is a friend, but also the first client for my business (Covers Girl. The website will be up after Liberty con. I just haven’t been home long enough to devote a weekend to setting it up.)
In this novel someone kills Hitler, and history diverges. The problem is that it’s almost impossible to convey in a cover, at first sight. I mean, if Hitler had been stabbed that would be doable, but blown up… well.
So, I tried to convey confusion and that the Nazis still go on.
She told me at the time she was inspired by Harry Turtledove covers. Most of the image was actually rendered in Daz/Poser, with some details added in by hand.
Note she hadn’t read the book: as she discusses here, a book cover needn’t be “the perfect scene from the book”, because that would only make sense to people who had read it! Instead, you’re trying to get people to pick the book up, and so you want to signal the genre and the general setting and subject matter.