If oid is a graphic tag, this function sets the path name for the graphic. If the graphic element supports a file reference attribute, that is used to set the path. If the element only supports an entity reference attribute, then a new graphic entity is declared and assigned to the attribute. When the parent document is a file system object, the new entity name is formed from the base name of the file (modified to be a valid entity name, if necessary). When the parent document is an object stored in a content management system, the new entity name is formed by prepending &E to a Universal Unique Identifier (UUID). If the path name is already declared as a graphic entity, then the existing entity name is used.

The path name value is stored as a relative path (as determined by graphic_relative_path) if possible, so that the reference is still valid if the document and graphic are moved to a different file system.

If oid is invalid, or is not the oid for a graphic tag, this function generates an error.