Album Art Import Error

Others have mentioned this problem but I don't see a solution.

I hoped that by making sure the option "Don't display first image from file directory as cover art" was unchecked, that the displayed image would be written to the tag automatically. This doesn't happen alas but I thought all I'd have to do was update the highlighted entries. Nope! That doesn't embed the artwork either. What's the point of being able to see the image if you can't update the tag with it? (Sigh.) Anyway given that's not the case (took me a while to realise and only when I copied the music to an MP3 player), I thought I'd try the "Import cover from file" option.

To make the action really simple I've got a program which batch resizes images to 245x245 and gives them a name beginning with an exclamation to make sure they appear at the beginning of the file list.

My first attempts using !.jpg or '!'.jpg and other variants gave the error message
<b>! front_245.jpg cannot be accessed
Note that there's a spurious blank inserted between the '!' and the rest of the name. There's no blank in the name. That makes me think that I can't use an exclamation in this context. Never mind. It's the first graphic, so I can use Format string *.jpg

No I can't - same message.

But, when I run the command as a Quick Action, it works perfectly. Only from the Actions list does it give the error message.

The quick action has no advantage over drag/drop image or 'Add cover' if I have to process albums one by one so I keep trying the batch option.

Step 1 - Changed the name of the jpg to start with the hash sign (#).
Step 2 - Ran the action again. Guess what! Got EXACTLY the same message again complete with '!' yet there's no longer an exclamation in the name.

Conclusion - the instruction is ignoring the current 'Format String' (*.jpg) and is using one from the list of previous (invalid) strings!?!

So all I have to do is delete the action and start again, since there's no way to delete the previous lines?

Nope! Deleted the action. Closed and reopened MP3Tag, recreated the action and the previous lines are still there.

HELP! PLEASE! How do I get rid of those old lines or get the action to run properly.