Images of a Hurricane Katrina-damaged library in New Orleans and Tulare County (Calif.) Free Public Library in Col. Allensworth State Historic Park founded by former slaves are part of the"Public Library: An American Commons" exhibition on display until June 12 at San Francisco Public Library's main branch. The hundreds of library photos from 16 states is the brainchild of San Francisco-based photographer Robert Dawson, who began the project in 1994.