Help for Newbie With Actions

there is a thread
/t/9691/1
that pretty much circle around the same problem.
The whole effort is only worthwhile if you have a lot of jpgs to rename.
Because in the end you have to handle each file individually if they all have individual names.

Renaming non-mp3-files is a task for the surrounding operating system.

So I think it is time to get acquainted with the good ole DOS commands dir and ren
Make a list of all jpgs:
Open a dos-shell in the topmost folder.
Enter
dir /s /b *.jpg > ff.txt
you get a textfile that shows all jpgs with the complete path.
a line might read something like
E:\MP3Musik\Klassik\Uri Caine Ensemble\1997 - Wagner e Venezia\wagner_wagner_e_venezia.jpg

You have to separate the jpg-filename from the path MANUALLY (or at least I can't think of a decent pattern to do that with search an replace) so that the formerly single line be comes 2 lines

E:\MP3Musik\Klassik\Uri Caine Ensemble\1997 - Wagner e Venezia
wagner_wagner_e_venezia.jpg

Now it is down the capabilities of your text-processing tool: it has to be able to deal with a "line end"
In Word this is ^p.
So a search and replace action in word would look like this:
Search for: ^p
Replace it with : "^pren "
This leads to lines that look like this:

E:\MP3Musik\Klassik\Uri Caine Ensemble\1997 - Wagner e Venezia"
ren "wagner_wagner_e_venezia.jpg

search for ^pE:
replace with: " folder.jpg^pcd "E:

this leads to lines that look like this:
cd "E:\MP3Musik\Klassik\Uri Caine Ensemble\1997 - Wagner e Venezia"
ren "wagner_wagner_e_venezia.jpg" folder.jpg

Save the whole file as text-file and rename it in the explorer to
ff.bat
and execute it.

If you want to keep the original jpg-files use the command copy instead of ren.
You see, this is all rather complicated. So you really have to have lot of jpgs to rename/copy.