When buying old photos, it is good to know more about them, especially if they have a photo studio name stamped on them. Having such a photo, I found this web page with an introduction to Hollywood Portrait Photography by David Shields. It lists some of the more known early day studios and photographers and the styles they were known for. It has a check list of the more noticed Hollywood photographers and studios in the field and a small sampling of photos from Shields personal collection. If you are into collecting classic film star photos, a place to get an idea about some of the more important studios of the day.
Link to Hollywood Portrait Photography by David Shields