We have found two pictures of George Cox. One, definitely the painter of the mural in the Lakeville, CT Post Office, is shown shaking hands with Postmaster Arthur Sommerfield. The other shows artist George Cox with David Siqueiros and Jackson Pollock. A George Cox was part of the Siqueiros Experimental Workshop in New York and is surely the person pictured with Siqueiros and Pollock. But we don't know for certain that this is the same George Cox who is pictured some 19 years later.
What we do know about the muralist George Cox is that he left the army in 1931, at which time he took up drawing. He was employed doing graphics design in the 1930s and received a commission for the Lakeville, CT Post Office in 1942. Following the War, he became the chief technical designer for the Brookhaven National Laboratory, where he worked until retiring in 1974. During that period he illustrated many publications and books for the lab, patented a design for a display easel, and designed the rather famous "Atoms for Peace" postage stamp.
Critical Analysis
Not having taken up art until age 21, Cox had a remarkable career. We have a glimpse of his earliest work in a lithograph dated 1932. We don't know for sure if he worked with Siqueiros, so that potential influence is unclear. We do know that Cox was very involved in community affairs, helping to form the South Bay Artists Association and a Bellport (Long Island) theater group. His name also appears a number of times in local newspapers in connection with the production of various art exhibits.