Nathaniel writes a sensible piece on what MTA's can do with the new
MIME features, but then makes a big mistake:
When a message of type
image/gif is submitted for long-haul delivery, it might reasonably be
translated to image/jpeg. Conversely, when image/jpeg data is received
for final delivery on a system with adequate storage resources, it might
be translated to image/gif for the convenience of the recipient.
Software to perform these translations is widely available.
WHAAAAAAT? JPEG is a "lossy" image format. I don't know what you
usually do with images, maybe you just look at them for a second or
two, but for some applications I would be very angry if the mail
transport decided to turn a GIF image into JPEG, thereby dropping
subtleties in the image that may be needed by my image processing
Although MIME currently only defines one audio format, more are likely
to be defined and registered with IANA in the future. In that case,
similar format conversion facilities might be appropriate for audio.
Again, I'd be more than disappointed if a piece of CD quality audio
that a friend prepared for me were turned into U-LAW by an MTA that
had nothing better to do.
Summary: CONVERSIONS THAT LOSE INFORMATION ARE A NO-NO FOR MTAS!
--Guido van Rossum, CWI, Amsterdam <guido(_at_)cwi(_dot_)nl>
"Oh Bevis! And I thought you were so rugged!"