I suggest to add new modules:
xmlns:enc="http://purl.oclc.org/net/rss_2.0/enc#" (see
http://www.xs4all.nl/~foz/mod_enclosure.html)
and
xmlns:image="http://purl.org/rss/1.0/modules/image/" (see
http://web.resource.org/rss/1.0/modules/image/)
Please mail me (porton@narod.ru) whether you will add these modules or a
user should use ->add_module() himself.