Cite

[Photograph of Indians on horseback, one with an umbrella]

MLA

[Photograph of Indians on Horseback, One with an Umbrella]. 0AD. https://collections.library.yale.edu/catalog/2010729.

APA, 6th edition

[Photograph of Indians on horseback, one with an umbrella]. (0 C.E.). [Photographic prints, Photographs, Snapshots]. https://collections.library.yale.edu/catalog/2010729.