Try checking the TOP Checkbox under Composition "Compose Messages in HTML Format" I do not know how an Animated GIF will show up in a Plain Text forward or reply ... you are lucky if your recipients see it AT All ...

Thanks for your help.

It is a jpeg that was converted to a gif file type. It is just a static picture.

I have been using the same .gif since 2015 with Thunderbird with no issue. I got a new computer and installed Thunderbird in January 2020 and it won't forward or reply with the image as a signature. New emails work fine.

So it is weird that the only thing that I can see that changed is the computer and maybe the latest Thunderbird.

Thanks again.

Does the signature appear in forwards and replies if the image is on the local computer, not a network drive? If it does, then the problem is the location on the drive. If it doesn't appear, then you should see if safe mode (hold Shift when you launch TB) makes any difference. Image signatures work here for locally-stored images, in forwards and replies.

Thanks for the reply. For troubleshooting, I saved the file to a jpg format. I saved it to the local C drive. When I create new email, the signature shows up.

When I reply or forward, it doesn't show up.

I switched to a html signature that I made online and I have the same problem.

So, when the image is stored locally, it doesn't appear in replies or forwards. And if you run TB in safe mode? There are quite a few add-ons that affect signatures and replies/forwards, so you might have one that is incompatible.

When I am running in Safemode, no change.

New emails shows a jpg signature. Forward and reply shows nothing.

I have a second computer that is now doing the same thing. It has worked flawlessly for about 10 years. Now signature isn't working.

Open Tools/Options/Advanced/General/Config. editor and type useremail in the search. Note the id number for the affected account. Type id6, or whatever number is right for the account, in the search. In the list, there are two preferences, mail.identity.id6.sig_on_reply and mail.identity.id6.sig_on_fwd. What are the values for the account? They should be true or false, depending on whether the boxes in Composition & Addressing for that account are checked or not. If the values are false and don't change when the boxes are checked, it suggests the prefs.js file in the profile is corrupted.

Thanks for this help. It is much appreciated. I am attaching captures of my results.

There is no id1.sig_on_reply.

Something is amiss. This is a new install from a new computer. I am going to uninstall and try to clean all of the remnants out of the registry and see if the profile is gone for ever.

Can you check Config. editor for the value of mail.ui-rdf.version? If it's not 17, you may be experiencing the bug with a failed profile migration, during the update to 68. This has happened with the paragraph/body setting, and I wonder if it applies to the signature settings.

You can create a new profile, without removing the current one, to test the persistence of the sig. settings. Help/Troubleshooting, about:profiles, to create, rename or run profiles.