Jackie, thanks again. No I did not know that you can "play" with the cover. I tried it and it worked (not always though). The only thing is that once you have the cover to full screen and you close the book, the full cover does not reappear the next time you open the book.
I discovered that if a book has pictures and you tap the cover picture a few times, a band of the book's pictures appear at the bottom, which pictures you can also enlarge.
The resolution of the picture has nothing to do with resulting in a full size cover. I have covers with a big resolution and the still do not appear full size.
Let's see what Seany at Moon+ comes up with in his next revision. In the meantime I keep my thinking cap on!