Note: If a contact doesn't have a photo when you think it should then click on the Gravatar and check the Photo tab. If a contact with that e-mail address exists in more than one address book the right contact might not get picked.
Please use the support forum or e-mail for reporting issues and incompatibilities: http://pirules.org/forum/index.php
This add-on supports any version of Thunderbird 3.0 and Seamonkey 2.0 final and above, including TB 3.2a1pre.
This add-on is not fully compatible with CompactHeader (the image always appears on the right side of the header regardless of the preference). I will look into this.
Let me know what other features you would like to see via #maildev, e-mail, my blog, or the support forum.