The caption can change a viewer’s understanding more quickly than the image changes their eye.

Words steer pictures. An image is ambiguous until something tells you what you are looking at, and once the words are read they are almost impossible to unread; the same photograph becomes a rescue or an arrest depending on the line beneath it. Interpretation gets set in about a second and then defends itself. Anyone choosing captions is doing far more of the work of meaning than the person who took the picture.

Try looking at a photograph before you read anything around it. Notice what you saw first, then read the caption and watch what shifts. That gap is worth knowing about.