Perhaps the most recognised picture from the war is this by Eddie Adams.
It shows the South Vietnamese General Nguyen Ngoc Loan executing a Viet Cong officer with a single shot to the head.
Photographs do not tell the whole truth, however. The prisoner had just killed at least eight people, which is what led Gen Loan to carry out the execution.
The image was to change the public perception of the war and haunted Gen Loan until his death.