You need to create a signature html files and then set settings to use it.

In Thunderbird opena new Write message and completely clear any contents or signatures. Leave a blank line - just trust me on this, it really does help. Create your signature just like typing an email - you are using Thunderbird to create all the html code. Add image as if adding an inline image. If you need to control positioning then use a Table.

Then save as a File Choose where to save eg: I created a 'Signature' folder in 'my documents' so I can keep all the various signature html files and any images I use in signature. SAve as html file type.

In Account Settings for that account select the 'Attach the signature from a file instead' option. click on 'Choose' and select that signature html file which you previously saved.

This link may help: https://support.mozilla.org/en-US/kb/signatures#w_signatures-stored-in-files

I've also added some images that may help.

Hello Toad-Hall,

Thank you so much! It's working but how to reduce space between lines in a signature.

Regards, Abhijeet