
Smithsonian Institution is a actually a collection of museums and galleries in Washington D.C. including the Freer Sackler Gallery, one of the largest repositories of Indian art. The photography collection is substantial,
although it can be hard to separate American Indian material from Indian material in database searches. The Smithsonian was involved in one of teh earlist Raj photography books, Through Indian Eyes.
One of the best ways to use the online database is to search by place in the subcontinent. The image above is by Lala Deen Dayal and is titled Portrait of Group of Brahmans, of Parbu Caste, in Costume.