Extended Still Image Registration

   The image/jpx content-type refers to all of the profiles and
   extensions that build on JPEG 2000 [ISO-JPEG2000-2] encoded image
   data. The file format is also defined in [ISO-JPEG2000-2], Annex M.
   The recommended file suffix is "jpf"

   To: ietf-types&iana.org
   Subject: Registration of Standard MIME media type image/jpx

MIME media type name: image

MIME subtype name: jpx

Required parameters: none

Optional parameters: none

   It is up to the implementation to determine the application 
   (if necessary) and render the image to the user.

Encoding considerations: files are binary and should be
   transmitted in a suitable encoding without CR/LF conversion, 
   7-bit stripping etc.; base64 is a suitable encoding;

Security considerations: see [RFC3745]. In particular, the Fragment 
   List (flst) box allows image data and metadata to be fragmented 
   across multiple resources reachable through a URL embedded in the 
   file. This feature is open to exploitation when a reader resolves 
   the flst box URLs without limitation. For example, an attacker can 
   exfiltrate local and remote files reachable by the reader processing 
   the image. In another example, this can result in the reader 
   attempting to resolve circular references.

Interoperability considerations: The ability of implementations to
   handle all the defined applications (or profiles within 
   applications) of JPEG 2000 may not be ubiquitous. As a
   result, implementations may decode and attempt to display the 
   encoded JPEG 2000 image data only to determine that the image 
   cannot be rendered either partially or in full.

Published specification: Rec. ITU-T T.801 | ISO/IEC 15444-2, JPEG 2000 Extensions

Applications which use this media type: Imaging, fax, messaging and multi-media

Additional information:

   Magic number(s): 12 byte string: X'0000 000C 6A50 2020
      0D0A 870A' (for all JPEG-2000 family files)
   File extension(s): jpf is declared at http://www.nist.gov/nics/. 
   jpx is also an acceptable file extension, although it is not 
   recommended for files on a desktop computer that are not directly 
   associated with a MIME media type
   Macintosh File Type Code(s): 'jpx '

Person & email address to contact for further information:
   1. Name: ISO/IEC JTC 1/SC 29/WG 1 Convenor
   2. Email: sc29-sec&itscj.ipsj.or.jp
   
Intended usage: COMMON
Change controller: ITU-T & ISO/IEC JTC 1