mailcap entries ignore filename/extension mismatches

[Eugene Lee <list-mutt@xxxxxxxx>]

I've run into an annoying problem, but I didn't find anything in the
list archives.  I get pictures sent from Outlook Express users.  Each
picture attachment starts with a MIME header like so:

        Content-Type: application/octet-stream;
                name="SomePicture.jpg"
        Content-Transfer-Encoding: base64
        Content-Disposition: attachment;
                filename="SomePicture.jpg"

Mutt (correctly) identifies the MIME type as "application/octet-stream".
And I'm pretty sure Outlook Express did the wrong thing and should have
sent a MIME type of "image/jpeg" based on the ".jpg" filename extension.
Since it is unreasonable to expect M$ to fix Outlook Express in the near
century, is there a way to force Mutt to determine the MIME type based
on the provided filename extension?  Any suggestions are appreciated!