Complex sentence: The album's cover concept was invented by Metallica and Peter Mensch, while the cover artwork was painted by Don Brautigam, who had worked with bands such as AC/DC, ZZ Top and The Rolling Stones.
Split into simpler sentences: The album's cover concept was invented by Metallica and Peter Mensch. The cover artwork was painted by Don Brautigam, who had worked with bands such as AC/DC, ZZ Top and The Rolling Stones.