Answer:
Images and captions label what time, event, and place the image is representing. It also gives us a clear representation of its purpose, what it is, and who made it. It's a clear image either drawn or taken a photo of. Take the Mona Lisa for example. It's just an image of a Venetian woman at first, but with more explaining and captions labeling its creator, origin, and the person in the portrait itself, the actual meaning is known.