The following is a guest post by Jan Grenci, Reference Specialist, Prints & Photographs Division. The Prints & Photographs Division uses Flickr to share interesting images with the world. Some of our Flickr albums aim to bring together images on a particular theme, from a variety of collections and time periods. Others ask for your help in identifying images with little or no caption information. Please allow me to direct your attention to three recently published albums. Dog Stars Though I am more of a cat person, I am fond of dogs and can appreciate the plentiful dog images found in the Prints and Photographs Online Catalog (PPOC). One of my favorites of the dog photos shows two of Herbert…