@kiwidude,
Just some positive feedback... I have used the 'replace cover' several times today. It's worked perfectly every time, including making sure any inline TOC link to cover works. I normally completely ignore inline TOCs as a waste of pages, but I made the effort to check.
As for what the filename of the cover is... I don't understand why anyone would care. In fact I quite like the fact that 'calibre moulded' epubs have a cover called cover.jpeg. It saves time having to work it out. Perhaps, I'm in the minority
