What’s up with anime thumbnail’s being so misleading?

Don’t know if anyone else has noticed this, but it seams like anime thumbnails are just getting more and more misleading over time. Probably one of the most annoying things is thumbnail’s with some random girl that isn’t even in the anime. Was watching some anime just now when I seen Kurumi Tokisaki (date a live) on an anime thumbnail who is literally not even in the show. The anime itself was pretty good, but why the fuck put a thumbnail with a character who isn’t in it?