Mp3tag doesn't rewrite a FLAC file when removing artwork. It just turns it into (or adds to, I'm not certain how it works) a padding metadata block. If the artwork was very large this leaves a very large amount of unused space within the file. An album that I just downloaded had 370kB cover images embedded in each file. I've removed them and now I have more than 380kB of padding in every file.
How can I remove this padding and control the amount of padding in a FLAC file?