@DiapDealer...What you say is certainly true for epub 3 ebooks for epub-only vendors(that don't use proprietary versions of the epub standard). But html code in blackest's thumbnail also contains the following tags: section, figure, figcaption etc and I'm not sure that those tags would work on Kindle's proprietary version of epub 3 because they are not listed in
Kindle's supported html tags list. Perhaps I've got it wrong(Kindle tag list out of date?) but I think Hitch would probably know more about this.