If I delete a tag(s) that contains artwork, and then click the undo option, the imbedded art is no longer in the tag.
Step by Step:
File has ID3v1 and ID3v2.3 tags, with imbeded artwork.
I have ID3v1, ID3v2.3 and APE checked in options-tags-Mpeg
I click delete tags
I click undo
Searched forums and read help, couldn't find any indications that the tag(s) would not be fully restored via an undo, so reported as a bug.
btw - new to Mp3tag...... great software - fantastic work!