Importing the Calibre library into the Sony Reader Library

[Fortissimo]

Hi all. I hope I'm posting in the correct section.

I started out with calibre, downloaded books from project gutenberg,etc. and requested for the relevant metadata, book covers, etc.
However, I was adviced to also get a feel for the Sony Library. Hence I imported the Calibre library folder into the Sony Library using the import folder facility in the Sony Reader Library file menu. Everything was okay, I got all the books and periodicals from the one to the other. However upon checking the Pictures folder in the Sony Library, I found it to be full of book covers as a result of the import from Calibre.
I'd prefer my pictures folder to have just the pictures I want in there. So my question is, should I just go ahead and delete these pictures? Will that result in my books not having any covers? Not the end of the world, but it brings to mind images of a paperback with the covers torn off. not very pleasant.

Also I'd like to know why despite downloading the relevant metadata, some project gutenberg sourced books don't display the book cover. An example is the adventures of sherlock holmes. On calibre, i can see the book cover on the panel at the far right of the computer screen, but when I click to open the book, the first page isnt the cover, but some words from/about project gutenberg.

I think I prefer the Sony Library as it looks so simple. Reminiscent of iTunes. So, I'll be syncing my reader to the library. Haven't gotten my reader yet, though. Just trying to get the feel of things as I await its arrival.