Originally Posted by kiwidude
The metadata inside the book file is only updated if you:
(1) Do a conversion (such as a conversion back to itself like ePub -> ePub)
(2) Save to disk/send to device (*)
(3) Use the "Modify ePub" plugin (*)
(*) Covers in a book are only updated in situations 2 & 3 above if calibre is able to "identify" the cover image that exists. It doesn't work for all formats, nor will it work for all books. The only cast-iron guaranteed way to force covers into your books is to do a conversion, or manually edit the book using Tweak ePub/Sigil/other eBook format editor...
Originally Posted by HarryT
You don't need to do a convert if you change the title - only the cover.
Interesting... I just spent the last few hours updating covers in Calibre and was planning to export ("Save to Disk"), delete the library, and then reimport the books. Although now I'm worried those changes will be lost unless I convert first.
All of my books are in mobi format. Is that one of the formats that work?
Or should I do a conversion first?