This page is an entry in the Key.

source

The term “source” can refer to any link in the chain of people and places involved in putting a photo before the viewer.

This includes the photographer who created the photo, the publication or website that published the photo, and the context in which the viewer saw the photo.

As the chain link explains, in most cases a photograph is only as trustworthy as the least trustworthy link in the chain of sources.