@uhoh It's not a caption, it's the description that photo has been known by since at least 1987.
It's also not the claim you are making it out to be. Anyone familiar with the photographic history of the Apollo program knows what photo is being referenced when someone says "The Only Photo of Neil Armstrong on the Moon." Or more specifically, "The only good Hasselblad photo of Neil Armstrong on the Moon."
@uhoh It's not an everybody knows it argument. Google it and you can find references all over the place. NASA describes it in official records: "This frame from Buzz's plus-Z pan is the only good Hasselblad picture of Neil on the lunar surface."
This room is set up as an echo chamber for previous statements to be reiterated by others, which in a way is an instance of "everybody is saying it". No reasonable conversation can take place here. I won't engage on this topic.