Images of 362 postcards from the Yale Divinity School Library's collection, primarily documenting missionary work in Africa (with a few from Asia and Oceania), are available for browsing on the American Theological Librarian Association's Cooperative Digital Resources Initiative's (ATLA CRDI) database. The postcards, dating from the 1910s-1920s, were produced by mission sending agencies to garner support for the missions' work and provide information about non-Western peoples and customs.
The Yale Divinity School Library also has made digital images from their collection available on the Internet Mission Photography Archive, which hosts historical images of Africa, China, Madagascar, India, Papua-New Guinea, and the Caribbean from collections based in Britain, Norway, Germany, and the United States.
...as reported in African Research & Documentation, no. 100 (2005), RGL call number: A A2583r