For sale is a lot of 19 miniature photographs showing scenes from San Francisco. Each one has a title on the lower portion, for example: "Bay Bridge, San Francisco".
They look to be from the mid-1930's. There is a copyright "Moulin" on the lower right of some, but not all, of the little pictures. In the mid-1930's Moulin Studio's was commissioned to photograph the building of both the Golden Gate Bridge and the San Francisco-Oakland Bay Bridge. Each photo is 3 1/2" X 2 5/8".
Read more about Moulin at http://www.moulinstudios.com/history.htm