Largest FirstThe function makes the largest artwork item the default (first), for every track. The item is assigned a picture type of Cover (front).
Delete all But LargestThe artwork is normalized then all but the largest artwork item is deleted.
Remove DuplicatesDuplicate artwork items are removed on a per track basis. An artwork item is a duplicate if its binary data exactly matches the binary data of another artwork item.
Progressive JPEG to BaselineThe items on this menu are used to re-encode progressive JPEG artwork items as baseline JPEGs. The Default menu item will only modify an artwork item if it is the default item (the first). All will modify all progressive JPEGs regardless as to their position.