If you're waving around a 22. then no. It's also a mind trick when looking at someone holding a .45 pistol from a distance, you judge the torso size in comparison to the gun. But in that photos case, yes, it is quite large for his hand size. I also forgot to mention peoples hands are significantly different. So it's all very subjective.
You seem to be missing the key word here; "Generally".
I'm not saying that "HURR ALL GUNS ARE loving HUGE AND EVERYONE IS handicapped AND THINKS THEY'RE LIKE WATER PISTOLS", I'm saying that, in general, people tend to think that guns are much smaller than they actually are