Well what you could do for cover art (depending on your actual structure of course, presuming that Album and Album Artist are contained in the path) is import all the media into the library ... at least temporarily. You could then easily tag [Album Artist] and [Album] using a mask created by the fill properties from filename (F12 key) and using the directories, instead of the filenames to embed the tags. Afterwards, you could set another template using the Move Rename copy tool.
Your choice afterwards to remove the files from the actual library or not. Of course this will not work for pdf files as you can't embed metadata in them (or at least I don't think you can.
I can't see how you would set up a script unless coverart and other assets have album artist and album as a distinct part of their filename. But maybe there is a way via a windows utility -- that's beyond me tho
Thanks at least I think you set me on a path to find out why I can't see the assets anymore by paper clip icon.
What I did is I stopped to use JR to automatically tag my files during import, instead I let JR use the tags I otherwise put to the music files. Is this the reason, that JR also doesn't tag the assets anymore and the don't show up as they are "untagged" now? Would I have to manually tag them as I did with the music files?
But my 3 main questions are:
Does JR only show assets with paper clip due to tags and not (as I thought) due to the fact that they are in the folder structure of the played music file?
If assets need tagging, why were PDF files also shown with the paper clip icon previously in my setup?
Is there a way to have paper clip icon shown without letting JR use it's tagging and instead use external tag information?
I now think they stopped to be shown because I removed the checkbox "write file tags when analyzing audio..."