MLA
Magnus, Charles. Confederate Photograph - Judah P. Benjamin, Secretary of War. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 4, Folder 56. https://digital.library.emory.edu/purl/668x95x7cn-cor.
APA, 6th edition
Magnus, C. (1862). Confederate Photograph - Judah P. Benjamin, Secretary of War (Box 4, Folder 56) [Card photographs (photographs)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/668x95x7cn-cor.
Chicago
Magnus, Charles. “Confederate Photograph - Judah P. Benjamin, Secretary of War.” Card photographs (photographs). Civil War Collection, 1862. Box 4, Folder 56. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/668x95x7cn-cor.