Depicts is a special type of statement, using the Wikidata property "depicts (P180)". It is the first suggested property to add to a file without any statements.
Description or probably details (planned feature) is a longer language-specific description of the contents of a file, probably containing some wikitext markup, analogous to description in Wikidata and "description" field in {{Information}} template.
Prominence is a mechanism for annotating multiple values for a statement. It allows users to improve the results of queries by selecting which values should be included in a search. Prominent statements have a "preferred" rank in Wikibase software behind structured data, where other statements have a "normal" rank. "Deprecated" rank is currently not supported.
Statement is a structured way of recording information about a file. A statement consists of a claim, zero or more references, and a rank; a claim in turn consists of a property and either a value or one of the special cases "no value" and "unknown value", and zero or more qualifiers.
