I have the latest version of Thunderbird, running on Windows 8.1. Today, I sent an email with Thunderbird. The email had 3 inline images. The 3 inline images got replaced, with 3 other inline images, from a previous email, that I had sent over 1 month ago! A copy of the older email, with inline images, may have been sitting in my drafts folder. I am not using imap servers. When I checked my "Sent" folder in Thunderbird, the inline images were replaced, with inline images from the "old" email. The content of the new and old emails was completely unrelated, so no chance that I just didn't notice that the wrong images were inserted. Maybe it's some kind of pointer bug, related to "linked list" buffers that store inline images?