It would be very nice if picard allowed for using a template (or maybe even scripting?) for naming cover art files.

Perhaps instead of the "Use the following file name for images", there could be "Use the following template for naming cover art files", for example mine might be:

"Cover_%T" where %T is the first-letter-capitalized primary image type.  This would result in images being saved as:

"Cover_Front.png", "Cover_Media.jpg", "Cover_Back.jpg"

A more flexible version might also provide a way to specify how to handle naming multiple images of the same type, rather than the current behavior of just adding " (1)" to the end of the file name.