Yeah but if you look at the photo, the shot has been made, the bullet enters Oswald, he grimaces in pain. Plenty of time for the sound of the shot to reach their ears yet none react to it. I looked this stuff up:
Speed of sound - 343.2 m/s (meters per second)
Speed of .38 caliber bullet from Colt Cobra revolver - 237 m/s
So basically the sound of the shot would have reached their ears pretty much the same time Oswald felt the bullet. Even though the bullet is slower than sound, at 343/237 m/s at those speeds it’s pretty instantaneous. So why would Oswald react but not them? If you watch the video of him being shot, he had absolutely no idea, never saw Ruby coming, so he is reacting to the pain. And in that video the crowd reacts as if it was expecting it just like the photo. No running, or panic, nothing.
I think you’re overreaching. Oswald was no doubt in a heightened state of awareness compared to the others in the picture, he would have been of necessity very tense and may have seen the gun before the shot was fired so his reaction to the pain would have been much faster than the other people’s reaction to the sound. The camera caught the image at the precise moment just before the others reacted.