Model to handle music release artwork
This is how I'd model it:

release (release_id, title, ...)

artwork (artwork_id, filename, width, height,...)

release_artwork(release_id, artwork_id, display_order)


All releases belong in the releases table, all artwork in the artwork table.

The release_artwork table joins the two, with the display_order column enforcing the display order. Insert the covers with display_order=1, then the rest (back cover, inlay etc) with 2, 3, 4... etc as needed - A simple ORDER BY display_order ASC will then deal with the ordering for you. If you want to doubly ensure the cover is first, you could always add a is_cover column to release_artwork and set it to 1 for covers.