Best way to do cover page

[ToboldH]

I have all my covers as 600x800, matching the resolution of the Gen3. Only, with the band at the bottom, this is actually too large.

I have been using a setting of 94% for the height of the image on my cover pages, but this could look better, as displaying an image at its original size generally makes for the best display.

I experimented with trying to center the image (making it smaller than 600x800), but vertical centering is not well supported (and messy, even in browsers), according to the resources I have consulted.

What do you guys do?