Manga covers on Kindle PW

I've recently put some manga on my kindle, and it works great, except for the fact that they don't have covers in library view. Is there something I can do to get them to show or create them? It shows a "cover" (the first page) when I turn the kindle off, though not in library.

The Funny think is I swear half of them started showing covers yesterday, but then today they don't have them again. Any Ideas?