I must assume that somehow they took their own picture.
If you read the caption, the picture was taken "at the British Embassy in Khatmandu, capital of Nepal, June 26, 1953"
No, it was the middle blocker from the team of sherpas that were playing volleyball up on top of Everest that particular day.
They had to interrupt their crucial third set to do it, but they did so graciously I was told.