The recording of war and how people were effected was changed by the use of photography.
The First World War was when photography was widely used to record the true horror and what life was like at war. The conditions the soldiers lived in, the informal moments and the effects of war and the injuries.
Images of war was traditionally captured by war artists and these paintings could be influenced by the army that commissioned the paintings, details could be missed and for reasons of moral and propaganda, a more optimistic picture could be painted.
The use of the camera made it possible for soldiers that could not draw to be able to capture the images of war, from the everyday life in the trenches, to the results of barrages and combat. Films could be easily sent back home to be developed and printed, or kept in a soldiers kit bag to be brought home later.
The use of photography in war could also be used by newspapers. The use of photography in newspapers required censorship, photography became used as a means of spreading propaganda. Photographs of happy soldiers going off to battle, the scenes of victory. What was often not shown was the armies defeated at battles, large numbers of dead and dying troops.
Famous 2nd World War photojournalist Robert Capa. He got very close to the action and recorded the troops lives and deaths.

Photographs of war have been used as evidence to aid the conviction of military and political leaders of war crimes.
2nd World War photographs were taken Henryk Ross by occupants of the Jewish ghetto showing people living their day to day lives in Poland. Some of these photographs were later used as evidence to prosecute war criminals. The photographs also showed what life was like for some of the Jews. Parties and social gatherings, children playing, the ghetto life was not all grim as had been conveyed. This does not alter the fact that the rise of Nazism and the unbelievable cruelty is deniable, just that there were times captured on camera people getting on with their lives.