|
There are multiple ways to specify cover images and various programs will use them inconsistently.
Many epubs will have 3 different cover images:
other.ms-coverimage-standard -- Regular size
other.ms-thumbimage-standard -- Small size
other.ms-thumbimage -- Extra small size for Pocket PC
There is also the older mobi spec for "EmbeddedCover" which is still used.
What I've found is that different interfaces will use one or the other image idiosyncratically. So just because there's a thumbnail image doesn't mean that a program will use that image for its thumbnail. It may use the standard cover instead.
Just because some programs will generate their displays with just one image, doesn't mean that all of them will. So I expect that the multiple images are there for industry-wide support.
|