Context and caption- without them we do not get the full impact of the image

I came across a photographic text book many years ago written in the forties.The article has stayed with me all this time.There were two pictures of a close up of two men with an extreme expression on their faces.they both looked like they had just heard the funniest joke of all time.There were no captions, but it is not until the end of the article that you are told that the image of the left was of a man laughing and the image on the right was of the instant that a man was shot. Until you are informed by the addition of text you in fact do not read the true meaning of the image.This has made me curious about the importance of captions on images as they complete the full intended meaning.Take for example the image here in each has a clue of added meaning based on its caption.Would you have the same interpretation of the what you connected with in the image if there was no caption. The three images of “Calm”,were in fact based on the word , it is what was the instigation of their creation, to find something that reflected and showed an aspect of calm.