Early understanding of photography was optimistic and rather naive. The new technology was seen, understandably, as a means of portraying the indisputable truth, but it was not long before a more complex reality emerged.
War was regarded by the populations in those countries involved as a heroic and even romantic, with young men seeking glorious victory in faraway lands. However, the introduction of photography during the American Civil War of the1860s had a significant effect on public perception and attitudes. The horrible realities of destruction and death were brought home to people who saw the images, and no one could see much in the way of glory or romance.
Military censorship emerged to a large extent during World War I. Governments realized that images of the horror and death would damage morale and possibly reveal damaging information to opposing forces. People also began to realize that images represented one photographer's view of a situation, and that another photographer's work could reveal a different angle on the same subject. Images of the battles of World War II were much more plentiful, and all sides used censorship to influence the reporting of news. Some pictures were very powerful, particularly those of the horrific Nazi concentration camps.
The wars of the latter half of the twentieth century, such as those in Korea, Vietnam and the Persian Gulf were much more fully covered by photographers although censorship was always a feature. Public opinion was undoubtedly influenced by some of the iconic images.