No, Post-Crisis, I disagree. You can enlarge the ebook file easily into the dimensions of a square. You get a different image because the front model becomes enlarged and the image falls out of the square background, but the resolution of the original is good enough so that it still works. If it was my cover, I'd just do this. With my copy without typography, it actually looks really good (Timothy, I rather not show the image without the artist's permission as it's an altered version of her original work).
It's an interesting solution. Is it still viable? I could still credit her and just add typography. I can ask her to do this as an option.
Problem is I think I'm back to square one. I still think I need her approval because it alters the look of her art.