Rated 4 out of 5 stars

Thank you so much for your work/plugin!

Love the enormous amount of smileys with all the skin tones.

However, a few improvements are needed IMNSHO.

* I know you can shift-click for Unicode instead of img, but unicode should be the standard. All the email recipients otherwise will get the message "for security reasons, some elements have been disabled". You don't want your recipients to receive such messages just because of a smiley, and you don;t want them to have an extra button to push just to see your smiley. It makes no sense. Even when the smileys are graphically better, img is NOT the standard way to go. Another solution would beto have a "unicode" checkbox in the smiley-menu to (un)check (of course remembered when Thunderbird shuts down).
* The button to switch on/off the emoticon panel should be next to the original emoticon button. I have seen with other plugins that it can be done. It is a message typing/formatting function and should be in the message formatting/typing command bar.

This review is for a previous version of the add-on (1.5.6). 

Thanks for the kind words and your feedback.

* I think it's a good idea to make image emojis a configuration option.
* The formatting toolbar is only present when composing an HTML message. It is not there for plaintext messages.