References from http: uris to media types without URIs

>From an http: URI that results in a representation with media type
image/jpeg, this document is self-describing because
1. The URI specification 2396 points to HTTP.  This is weakly done in the
example section with
   "http://www.math.uio.no/faq/compression-faq/part1.html
        -- http scheme for Hypertext Transfer Protocol services"
2. RFC 2616 (HTTP) specifies that media types are registered at Iana [17]
where [17] is RFC 1700, Assigned numbers (actually numbers and values)
3. RFC 1700 has a media types section that contains image/jpeg that refers
to RFC 1521

Cheers,
Dave