These are reportedly the first naked photos of Madonna made when she was 20 years old. They were later appeared in Playboy.
Not the most arty photos I've seen. Some other exhibits on display (as per below) were more interesting to me. These photos are on show (sale) at Impure Art gallery, 19 Earlham Street, Seven Dials, Covent Garden, London WC2, till 19 July.