Thunderbird: embedded images not rendering inline

This may not be the most appropriate place for this, I have posted to the Mozilla boards but I'm guessing SO gets a few more eyeballs... Anyway:

We're generating an HTML email with inline images. They display fine in Outlook 2007, but do not render inline with Thunderbird 2.0.0.23, they show up as attachments. I have the following set in my thunderbird client:

Display attachments inline: tick 
Message Body As: Original HTML 

As far as I can tell the various headers are correct (from Thunderbird view source):

------=_Part_1_9884354.1303120232543 
Content-Type: image/gif; name=classpath_466bd94ae6b_before.gif 
Content-Transfer-Encoding: base64 
Content-Disposition: inline; filename=classpath_466bd94ae6b_before.gif 
Content-ID: <classpath_466开发者_运维技巧bd94ae6b_before.gif>

and the HTML (Thunderbird source):

<img title=3D"Before" alt=3D"Before" height=3D"13" width=3D"52" src=3D"cid:classpath_466bd94ae6b_before.gif"/>

Everything looks good per the docs, any suggestions appreciated.

Thanks

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I had the same problem and solved it by changing Content-Type: multipart/mixed; to Content-Type: multipart/related; (in the MIME of the constructed email)