On this date in 1968, General Nguyễn Ngọc Loan summarily executed a Viet Cong terrorist named Nguyễn Văn Lém during the Tet Offensive in the Vietnam War. The general was filmed and photographed as he shot the prisoner with his personal weapon. This image was widely used by the Left and the anti-war forces to discredit our South Vietnamese allies . No one ever mentioned that the terrorist and his death squad had just murdered the entire families of several policemen. The terrorist was not in uniform, and did not fight according to the articles of war, so he was not a POW. The execution was both legal and justified.
A deeper question is the fact that the photo was printed at all in a time of war. Could you possible imagine a US newspaper in 1944 or 1918 printing a similar picture? Because there were plenty of summary executions by our allies in both of those wars.