What’s the easiest way to update album art

So, you want to fix embedded album covers by exporting and re-importing them? Here we go:

MP3tag has a rarely used feature called Actions which is designed for such tasks.

Export cover to file

Exports the cover art from the tag of the file to the relative or absolute filename specified by the format string. You can use placeholders like %artist% and %album% in the format string.

Remove fields

This action type removes the fields entered in the edit field (e.g. COMMENT;PICTURE). Removing embedded cover art. Please use PICTURE as field name if you want to remove cover art from the tags.

Import cover from file

Imports the cover art specified by the absolute or relative filename into the tag of the file. You can use placeholders like %artist% or %album%.

In your case, you want to

2. Export all embedded covers to file
   • Open mp3tag and insert all your music files
   • Select all files and go to Menu bar » Actions » Actions (quick)
   • Choose Export cover to file
   • Enter %_filename% as format string for image filename
     You get a nonsense message but all covers are exported to their respective folders
3. Delete all embedded covers
   • Select all files and go to Menu bar » Actions » Actions (quick)
   • Choose Remove fields
   • Enter PICTURE as fields to remove
     Don't be confused if you look at Windows Explorer after it. He doesn't update the file covers.
     You have to copy (not renaming) a file to check the successful removal.
4. Re-Import all file covers
   • Select all files and go to Menu bar » Actions » Actions (quick)
   • Choose Import cover to file
   • Enter %_filename%.jpg as format string for image filename

Got some errors on the last step? Thought so. Me too. I realized that some embedded pictures are saved as .PNGs rather than .JPGs. Ok, back to the import dialog and enter %_filename%.png for our second import try. This time, all .PNGs are imported

Both programs you mentioned already do this. However, once you upload the file somewhere else, you cannot prevent the server from removing album art again, if it decides so.

Also, ID3 tags are a finicky beast, and it could be that the server doesn't recognize the specific format you're trying to use:

• Try different image formats – JPEG vs. PNG;

• Use iTunes or foobar2000 to convert the ID3 tags between different versions (e.g. iTunes writes ID3v2.4, but quite a few tools only support v2.3);

• Use mp3Diags to make sure the ID3 tags aren't corrupted (though note that it sometimes gives false positives for v2.4).