Philadelphia City Archive
PhillyHistory.org, the website of the Philadelphia City Archive, gives the following descriptive information:
The City's photo archive contains over 2 million photo records that date from the late 1800's. This web site contains a growing collection of those photos. All archive photos may be searched by keyword and date. Archive photos which have been assigned a geographic location are also searchable by proximity to an Address, Intersection, Place Name, or Neighborhood.