“Cindy Sherman” through June 26 at Metro Pictures (519 W 24th Street between 10th and 11th Avenues, 212-206-7100). “Spencer Tunick: Public Works 2001-2004” through June 19 at I-20 Gallery, 529 W 20th Street, between 10th and 11th Avenues, 212-645-1100). “Hilary Harkness” though June 26 at Mary Boone (541 W 24 Street, between 10th and 11th … Continued