The caption is like the title of a painting. It does not so much tell what the image is an image of, but what the author/painter tells us their image represents

The caption is like the title of a painting. It does not so much tell what the image is an image of, but what the author/painter tells us their image represents. Represents, not depicts. Or consider a song, it's title does not tell where the sound was recorded, but what the composer tells us the song is about. Not where and when it was recorded.