Shown on the image, from left to right: Giulio Andreotti, Takeo Fukuda, Jimmy Carter, Helmut Schmidt, Valéry Giscard d'Estaing. The latter two initiated the G7; its first meeting was hosted by Giscard in 1976, at Château de Rambouillet.
German chancellor Schmidt was about as grumpy as he looks in the picture; Jimmy Carter can tell you a thing or two. Schmidt felt that he needed to reprimand Carter for his naivety with harsh lectures. One of them was said to have made the US president cry.