On the very day I posted my lengthy iTunes upload workaround, Apple go and release 10.4.3 which totally breaks it.
Specifically, “Get Specified Finder Items” no longer works as I like, and you can read more about what they’ve done to make it FUBAR at Mac OSX Hints.
In order to get the workflow to work correctly, by sending the uploaded files to the Trash so that your artwork folder can update, you have to perform some other action on your artwork.jpg first.
At first I tried labelling it, but that threw up an error, as did trying to rename it. In the end I settled for placing the “Move Finder Items” action just before “Move to Trash” and setting it so that artwork.jpg is moved to the Desktop before going in the Trash.