Yep, I understood but thought thumbnails
may be of interest given you first mentioned image types.
PhpDig is a text indexer, not a file type indexer, and what you're asking is outside of what PhpDig does. For example, seach
hamlet and get results, but search
hamlet.doc and get no results, meaning that file type is not a part of what PhpDig can do, as PhpDig searches keywords from a document.