Thunderbird/SnagIt missing image

  Thunderbird missing image 
  Originally uploaded by ppival.

I'm sending this question to TechSmith technical support as well, but in case it's more of a Thunderbird issue than a SnagIt issue I thought I'd try the lazy web too.  I'm using Thunderbird 1.5 and SnagIt 8.2.  I can easily grab a screenshot in SnagIt and paste it into an email, but when I try to paste a second image, I get this little red error box, and have to save the email to drafts, close, then re-open it in order to be able to paste the next image in.  Sometimes I can do two or possibly even three images in a row (I think), but if I'm doing multiple images, I can pretty much always expect to run in to this.  It really slows me down, and if there's a way to fix it I'd love to know - anyone have any ideas?