Converting seemed to work, just tested on one that had the Penguin logo on the cover of about 5 books in a series. Had updated the image but when exported to the Kobo it was the Pengiun again. I opened the book in Calibre and same thing. Converted it, opened the new EPUB and it had the new image, so I deleted the ORIGINAL_EPUB format
Will have to sort out the others later in the week when there's time. Thanks for the tip. Happy with Aldiko now with all the tweaks and title changes to organize things.