MLA
Souvenir Post Card Co. (N.Y.). Down in opossum country : an African American woman and child standing outside a wood house : with a dog. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/24298sf7ng-cor.
APA, 6th edition
Souvenir Post Card Co. (N.Y.). (unknown)[Down in opossum country : an African American woman and child standing outside a wood house : with a dog]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/24298sf7ng-cor.
Chicago
Souvenir Post Card Co. (N.Y.), Down in opossum country : an African American woman and child standing outside a wood house : with a dog, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/24298sf7ng-cor.