In practice
Image metadata is the data about a photograph that travels with the photograph. It splits roughly into two families. EXIF is written by the camera and records capture data — date, time, exposure, lens and so on. IPTC is added by people and carries editorial information: caption, credit, copyright, keywords and usage notes.
For stills delivery this is not an afterthought. A press office or picture desk relies on embedded captions and credits to publish an image correctly and to search a large set. Missing or wrong metadata leads to mis-credited photos and frames that cannot be found.
In a unit stills photography workflow, captions and credits are often added during editing and stored alongside the RAW file in an XMP sidecar, then embedded into the exported files. Well-captioned key selects are far easier for publicists to use.
For how metadata should be set when handing over a shoot, see our guide to delivering approved stills.