There are numerous sources of images relating to the Anthracite region available on the Internet. Below is a select list of libraries, archives, museums, and other sites that have particularly rich collections.
Deltiology is the study and collection of postcards. Historic postcards are an excellent way to research historic places and buildings, especially ones that do not exist anymore. A number of libraries, archives, and museums have digitized their postcards and made them available online. Below is just a selection.
Postcards are often quite difficult to date. The links below provide useful information about how to date, identify, and interpret historic postcards.
(Above: Entrance to the mine at Coaldale, Pennsylvania, circa 1915-1930, National Trust Library Historic Postcard Collection, University of Maryland Libraries)