The following is from the New York Times, March 18, 1923:
Why did you want to climb Mount Everest? This question was asked of George Leigh Mallory, who as with both expeditions toward the summit of the world’s highest mountain, in 1921 and 1922, and who is now in New York. He plans to go again in 1924, and he gave as the reason for persisting in these repeated attempts to reach the top, “Because it’s there.” “But hadn’t the expedition valuable scientific results?”
“Yes. The first expedition made a geological survey that was very valuable, and both expeditions made observations and collected specimens, both geological and botanical. The geologists want a stone from the top of Everest. That will decide whether it is the top or bottom of a fold…”
Had Mallory made it to the summit, he would have collected rock samples. These rock samples were not searched for when Mallory was discovered in 1999. Hillary collected rock samples in 1953. The Chinese collected rock samples in 1960.
Regardless of whether they made the summit, rocks can be analyzed to determine the altitude they were collected from.
Andrew Irvine had zippered pockets — a new invention back in 1924. Had he made it to the summit, the most likely evidence would be summit rocks in his pocket. Even if he was carrying a camera, if the weather was not clear (which it was not prior to 4PM), there is no guarantee he would have taken a picture.
My search for Irvine is primarily focused on recovering rocks to establish how high he made it. It is very unlikely that any film from a camera could be recovered and successfully developed.
There is no contemporaneous evidence that Mallory intended to leave a picture of his wife on the summit. This piece of the story was provided years later. It is unfortunate that in their rush to find a camera and a photo, the 1999 search team destroyed the evidence that would have shown whether Mallory and Irvine made it to the summit.