2) Terms and Conditions: https://www.digitalcommonwealth.org/copyright
3) Collection Summary according to their website: Digital Commonwealth is a non-profit collaborative organization that provides resources and services to support the creation, management, and dissemination of cultural heritage materials held by Massachusetts libraries, museums, historical societies, and archives. Digital Commonwealth currently has over 130 member institutions from across the state. This site provides access to thousands of images, documents, and sound recordings that have been digitized by member institutions so that they may be available to researchers, students, and the general public.
In addition, Digital Commonwealth members may apply for free digitization services from the Boston Public Library as part of a grant awarded by the MBLC (Massachusetts Board of Library Commissioners) and funded by the LSTA (Library Services and Technology Act).
The Digital Commonwealth is a web portal or gateway to digital assets hosted by Massachusetts cultural institutions. Cultural institutions include libraries, museums, historical societies, archives, research institutions, and other repositories of our cultural heritage. Digital Commonwealth uses Open Archives Initiative (OAI), a protocol for metadata harvesting, and Dublin Core. Dublin Core is an international metadata standard that has been for describing countless digital collections worldwide. Simple or Standard Dublin Core consists of a set of 15 optional and repeatable elements. The elements are used to provide information about an object, such as its title, creator, date, subject, etc. For Digital Commonwealth, Dublin Core (encoded in XML) will be harvested via the OAI protocol and incorporated into the search index.
4) Listed with each photo is relevant info and a handy citation generator:
Chicago Style: “Social Religious Building, George Peabody College for Teachers, Nashville, Tenn..” Card. 1930. Digital Commonwealth, http://ark.digitalcommonwealth.org/ark:/50959/bz60d201n (accessed September 14, 2016).
Title: Social Religious Building, George Peabody College for Teachers, Nashville, Tenn.
Date: [ca. 1930–1945]
No known restrictions on use.
5) CC_Social Religious Building, George Peabody College for Teachers