I haven't looked at how/why it's done, but instead of being generated on the fly, they seem to be pulled & stored in the system folder. In the very few tests that I've done, I only got proper covers when downloading stuff from my archive on the device itself, or from a sync.
Putting a (still DRM'ed, metadata untouched) azw/azw3 from a 'Transfer via Computer' DL doesn't help (unless you happen to do a sync after, I haven't checked, wireless was off during my simple tests). (EDIT: I'm stupid, that's because I *sent* them via Calibre, and the asin got squished... cf. the multiple threads about it in the calibre/kdev forums)
FWIW, here's the filename syntax:
And the few that I checked are (badly) downscaled at around 232 or 262 px high (with a builtin-in fake drop shadow on the bottom right), and like before, don't seem to care much about aspect ratio, width varied much more than height.
(The 'portait' bit is slightly funny, because the Home screen doesn't handle screen orientation... Someone might want to check what happens with ixtab's orientation patch, though).
The framework does seem to sometimes try to build these from the file, because I do have broken/empty thumbnails of calibre generated newsfeed (with a .partial suffix)...
Last edited by NiLuJe; 05-08-2012 at 06:18 PM.