He’s been called “the Cartier-Bresson of the 21st century,” a compliment that makes sense for a photographer who began as a graffiti artist. When the young JR found a camera in the Paris Metro, his graffiti switched from paint to photographs—gigantic black-and-white imagery he swathed on buildings and in public spaces. His images soon became installations. For this exhibition JR has created digital murals of San Franciscans stopping to chat and going about their day. —L.J.