"This document specifies metadata properties intended to be used primarily but not exclusively with photos."
This document includes the IPTC Extension schema, which "extends and complements the IPTC Core schema by a set of more granular properties and further specialized rights related properties from the PLUS metadata schema."
"This document is designed to familiarise photographers, photo editors and metadata managers with the use of the IPTC Photo Metadata. It provides a short guideline on the use and semantics of each IPTC field (also called metadata property)."
"This standard defines a set of metadata elements for raster digital images to enable users to develop, exchange, and interpret digital image files. The dictionary has been designed to facilitate interoperability between systems, services, and software as well as to support the long-term management of and continuing access to digital image collections."