Historical photographs are important because they provide an accurate primary source for historians. Images may provide more reliable information than written primary sources, which can be affected by bias or mistaken beliefs.
Historical photographs also provide additional detail on cultural surroundings, such as typical clothing and styles of the time or common household objects. Military photographs depict old-fashioned weaponry, uniforms and troop maneuvers. Historical photographs have also preserved images of some indigenous peoples whose traditional lifestyles were destroyed by colonization and forced assimilation. Historical photographs also help provide records of atrocities, such as the Holocaust, which helps prevent those tragedies from being forgotten by modern people.
Historical photographs are also valuable teaching tools because they help students engage with the subject. Portraits or other images help students visualize the past, which may be difficult from text alone. Photographs can also help students understand what is being discussed in a more concrete way. Some teachers have found that centering group discussions around images can create a more lively discussion. Photographs can also be valuable starting points for explorations of the time period. For example, a series of portraits of recent immigrants at Ellis Island can lead to a more nuanced discussion of immigration policy and the mix of cultures that makes up the United States.