Originally Posted by kiwidude
I see 44reader suggested Modify ePub, however you mention you personally use mobi formats. If you are looking to stick with mobi only then there are no plugin tools to help. One reason why so many of us use ePub as a master format - so you can use Modify ePub to insert metadata jackets and replace covers without doing ePub -> ePub conversions. However that will still leave in your case (as it does in mine as a Kindle owner also) the need to then do an ePub -> Mobi conversion at the end.
Depending on how an existing cover is defined inside your existing mobi files, you may find in some cases that calibre will substitute in the latest cover for you anyways when sending the mobi to your device, without going down the ePub route. However that is a dice roll though, it depends on the manifest inside the mobi file and whether it already has an existing cover. If you have converted it with calibre already then it should be replaceable. So you could generate a new cover using this plugin, then send to device/save to disk and see if the new cover is inserted.
thanks kiwidude & 44reader.
I currently just re-send the original mobi (minus restrictions) back to the kindle so that any series info will be added to the title, then I run kindle collection manager. By not sending a converted file I haven't lost the original sync and share feature along with the recommendations for other books. The downside is that I have to live with amazon's lack of book description.
I create and save a master epub file from the mobi file so I could convert (thus maintaining the original epub) then tweak the new epub. Converting that epub to mobi then checking and correcting exth headers (much easier now, thanks kiwidude), would give me almost the same features as an original amazon mobi, with a book description, to then send to the kindle.
I'll have to play around with various options after I get done at work and complete the almost due continuing ed.