Some photos tell stories. They do more than entertain the viewer’s eye. They engage the brain, sometimes in subtle ways and sometimes in obvious ways.
Often they do this with clues. There may be objects in the photo that hint at the time and place or the background might offer some information. This is especially useful for documentary style photos.
When we are documenting something with a photo we need to give information visually. Items carefully composed within the photo can do this and give our photos context.