On Tue, Aug 20 2013, Mark Walters <markwalters1009@gmail.com> wrote:
> What does the (mis-behaving)  part button say? is it [image/jpeg] or
> [application/octet-stream as image/jpeg] or? and what do correctly
> behaving part buttons say?

Hey, Mark.  That's the perplexing part: the parts seem otherwise very
similar.  For the case of the part that is *not* handled correctly, the
Content info and button are:

  Content-Type: image/jpeg; name="photo.JPG"
  Content-Transfer-Encoding: base64
  Content-Id: <...>
  Content-Disposition: inline; filename="photo.JPG"

  [ photo.JPG: image/jpeg ]

And in the case of a test message that seems to behave as expected:

  Content-Type: image/jpeg
  Content-Disposition: inline; filename=monkey.jpg
  Content-Transfer-Encoding: base64
  Content-Description: monkey!

  [ monkey.jpg: image/jpeg ]

In the first case clicking on the part button has no effect.  In the
later case the image opens fine in the external viewer.

I guess the only other difference is the rest of the MIME structure that
these parts are embedded in...

jamie.