Vannerson's portraits of Native Americans were part of a systematic effort to document members of treaty delegations who came to Washington, D.C. Delegation photography was a routine part of every state visit. Many portrait studios, including that of James McClees, for whom Vannerson worked, profited from the business. At the height of the winter season of 1857–58, for example, approximately ninety delegates from thirteen tribes were in the city. Bound as albums or offered as single, hand-colored prints, the portraits, including the standing portrait of Shining Metal, a chief of the Mdewakanton Dakota, were sold to a curious public.
Merry A. Foresta American Photographs: The First Century (Washington, D.C.: National Museum of American Art with the Smithsonian Institution Press, 1996)