Itzhak Bar-Ziv was a young chess player in 1964, and he was one of the staff in the chess Olympiad held in Israel that year. He shot quite a few candid photographs of the players. Above is one such photo, showing (l. to r.): Keres, Eshel (Israeli Chess Assoc.), Botvinnik, Smyslov (back to camera), Ben Gurion (Israel's prime until 1963, holding a scroll and the cup), Darga, Petrosian.
(Thanks to the reader J.K. for correcting two mistakes in the original post.)