Add an animated signature to Thunderbird

Steps

1. Design your signature on BylineSig, then click Copy HTML.
2. In Thunderbird, open the menu and choose Account Settings.
3. Select the account you send from.
4. Under Signature text, tick Use HTML.
5. Paste the HTML into the box.
6. Close Account Settings and write a new message to check it.

Keep the image hosted

If Thunderbird offers to attach the image to the message, leave it unticked. Attached, the GIF is embedded in every email you send and adds its full size each time. Left alone, it loads from our server.

Does the animation play?

Thunderbird animates GIFs. It also blocks remote images by default when reading, so a recipient using Thunderbird sees your contact details and links as text until they allow remote content for the message.