Originally Posted by vice-versa
Since the beginning of october (so since I bought my Glo) I have already read 5 books and is currently reading an other (all side-loaded boks, converted as epub to epub within Calibre, from two different series). None of them had margin around the covers. Perhaps its a problem of proportions ? I have a numeric frame to show photos and as my camera takes 2/3 photos, all are cut down by it (it's meant to display 4/3 pictures) except vertical ones that are framed by black margins. I suppose that rather than strech the cover to fit the screen, the firmware add margins.
Yes, that is what is happening. If the image used in the book is a scan of a paperback cover, the proportions are different to the Kobo ereaders screen. If that was simply being used as the cover, it would either be displayed with white bars down the side, or stretched horizontally. But, as the first page is used, it depends on the code in the page for displaying the image. This can display the image at it's natural size, resize to fit the screen but keep it proportional or stretch to fill the screen.
If you are using calibre and sending the covers over, it stretches them to the appropriate size.