The South Carolina Historical Society, http://www.schistory.org, was established in 1855 and continues to "record and preserve the past for the sake of the future." Their website is easily navigated and offers links to publications, archives, photographs, as well as access to the Society's own private collections, all having to do with the cultural, architectural, and geneological history of South Carolina.
The Cities/Buildings Database, http://www.washington.edu/ark2, is an online resource that provides an international collection of digital images comprised of both buildings and cityscapes taken throughout history. Upon entering the database link, pictoral information may be sought using a table of advanced search options. Search by title, site, architect/builder, location, date, material and so on.
The Historic American Building's Survey/Historic American Engineering Record, http://www.cr.nps.gov/habshaer, is run by the National Park Service with available links to their administrative records and print and photo division, with the option to place orders for hard copies to be shipped for research purposes. The site also features links to the Library of Congress and the National Archives sites.