Historical fiction is a complex genre. It can strive to be as absolutely accurate as the writer can make it (as I attempted in Crispin: Cross of Lead) or it may go no further than to create a general sense of time and place (as in Midnight Magic). The work that is merely dressed up in a general sense of time and place is rather like a musical comedy. There is nothing inherently wrong with this approach, and in fact there are some real advantages. The primary advantage is that one can deal with very modern ideas and simply place them where one can have the most fun.
Powerful photographs helped change the tide of the Civil Rights Movement of the 1950s and 60s. Some of these very photos moved author Elizabeth Partridge (goddaughter of the influential photographer Dorothea Lange) when she saw them 40 years later. Consider the role that photographs, books, and interviews play in historical research as Partridge discusses her process of selecting viable sources for Marching for Freedom: Walk Together Children and Don't You Grow Weary (Penguin, 2009).