Production and the page
Caption
Also: cutline
The line of text under a photo that says what or who it shows. Americans often call it a cutline.
A caption tells the reader what they are looking at and, often, why it matters. It should add information, not just label the obvious. Get the names right and in the correct order, left to right, because a wrong name under a face is one of the surest ways to draw a complaint. Simon's photo factsheets cover this in detail.
Simon on this
Where Simon Townsend teaches this in the archive: