Photographs, drawings and other images provide information you can't always get from a text source. Images can provide details of everyday life such as clothing or material culture.
It is important to keep in mind that photographs are not an unbiased reflection of reality -- the photographer chooses what and how to depict a certain scene.
For more information on images see Finding and Using Digital Images. Additional collections of digitized government documents can be found on within the research guides for various regions and topics. Also see Historical Visual Materials Collections guide for information on photographs, architectural plans, postcards, historical maps, artwork and ephemera available in Special Collections.