Hi
Looking for some help please - not sure if this is just Paperwhite or all Kindles? Apologies if posted in wrong place or asked before......... but

Have very recently got hold of a Paperwhite - already own a number of ebooks in mobi or epub format so have used calibre, where necessary, to convert to mobi and then have transferred via usb to the Kindle. So far so good, can read the books all fine ........... but

The book covers do not show, even though they are embedded in each file. I've also in frustration added separate jpegs for each cover to each folder - all to no avail?

A stupid question perhaps but do they have to be B&W or grayscale and is the Kindle sensitive to size? They are all 600x800 which appears to be the standard.

Is there a 'naming' requirement?

Anyone else had this or know the answers please, would be much obliged for some help.