One clue gives the answer.
Getty Images says:
Willie Mays #24 of the San Francisco Giants bats during an MLB game against the Chicago Cubs circa May, 1960 at Candlestick Park in San Francisco, California.
Presuming “circa May, 1960” is correct, I started looking there.
The Cubs played a four-game series against the Giants at Candlestick Park in May 1960, their first visit to the then-new Giants ballpark.
The clue that gives this away is the Cubs...