Problem: In v2.38 Ctrl-R to remove tags, then ctrl-z to undo remove doesn't put back the cover art.
Steps to reproduce: Load a file with embedded cover art. Select the file. Press Ctrl-R to remove the tags. Press Ctrl-Z to put back the tags.
Results: The embedded cover art is not put back.
Expected Results: The embedded cover art should be put back along with the other tags.
Why do I want to do this: This is a fast way to rewrite tags into my preferred format. 
This is a known issue but it's not a bug. Cover arts are pretty large and take up a lot of memory space. If Mp3tag was to save a copy of the covers in RAM, loading a library with several hundreds of files would take up ages and would also eat up all your RAM.
I would still consider it a bug, but I won't quibble. Perhaps we need a new category. Instead of this being an [x] then how about [kiwf] Known Issue Won't Fix
I understand the issue, but it's a case where the user should have the option of whether or not to store the image files in the undo buffer. If the user wants to load up his ram so he can undo a huge operation like that, then that's his choice.
How big is the average album art? Mine's around 20kb, and I have around 7000 files. That would be around 136 meg. Not very much for RAM. (and I certainly admit that mine isn't a representative collection. I'm just using it as an illustration)
Perhaps a new global option that is off by default: "Delete Album Art Undo-able" and give the user control.