Please mark this resolved so others do not see it as a fresh post. Thank you.

The above post IS my first post. Here is a correction. It's only the font size in my signature that has shrunk since the latest Thunderbird update. The image in the signature is still the same size as it was before the update. I would like to know HOW to make the signature font size the same as the message font size.

I responded to your first post. This was your second post. You need to post screenshot of your sig HTML

If anyone know what my "HTML sig info" is, and where to find it, please tell me.

You stated you have a signature. Please share what it is. If it is plain text and messages are plain text, there is no need to change. You're asking for help but not sharing the text that needs help.

My signature has been the same for years. Nothing has changed. It consists of three lines of plain text: my office phone, my mobile phone, my website address (which is hyperlinked) and an image (which I believe is a jpg). I really don't care to share my phone numbers here.

Ok, that's good to know. Plain text does not have a size attribute, which means that your recipients will continue to see your messages as they are now.

On second thought, if your website is hyperlinked, it may be HTML. Again, we need to see it. You could make a screenshot and black out the phone number.

My latest test (emailing myself) now shows my message text and signature text are the same size. That's as they should be, and always have been, until recently (without any changing from me). So, I don't know what has just happened. However, now both the message text and signature text are in an extremely small font. Perhaps 6? I think I've been seeing size 13 or 14 until now. Should I now change the text size in my inbox?

Font size is now an option under the menu. Click that, and see if available options meet your needs. What you are experiencing is how you see the messages in thunderbird, not how recipients see it. As I mentioned earlier, there has been no change in your actual email.

When I try to increase the font size in my inbox (View, Font Size, Increase Font Size) the font size of message titles in my Inbox increases, but the font size of the actual message stays the same.

In an earlier post, I put 100% of what you need. Give it close attention and it works perfectly. https://support.mozilla.org/en-US/questions/1437527

It just keeps getting stranger and stranger. Now, each time I email myself as a test, the email disappears from my inbox in a matter of seconds.

Regarding the instruction 1437527 above, I can follow them until I get to "- and, if you have account set to compose HTML, then set that in tools>settings>composition ...) but I don't see any "composition" choice, so can't go any further.

You're saying there is no composition option? See attached. I am beginning to get annoyed with your continuing change of your problem.

From David: "You're saying there is no composition option? See attached. I am beginning to get annoyed with your continuing change of your problem."

Nothing is attached to your email.

Hopefully someone else will offer some help. I'm going to close everything and try restarting my PC. Then I have other things I need to accomplish today.

Hopefully someone else will offer some help. I'm going to close everything and try restarting my PC. Then I have other things I need to accomplish today.

You apparently have issues and expressing the in a manner others can understand is one of them. I have read through this and your other topic and honestly I simply do not have a clear views of what the problem is.

Perhaps review the support information on signatures and how they should be created. https://support.mozilla.org/en-US/kb/signatures The images are for old versions, but the information on where signatures are set and how to create them are still unchanged.

As for the image you do not see in your email. I have no idea, but it is clearly visible in the forum thread, so look there for it. Here is a link to the response https://support.mozilla.org/en-US/questions/1446642#answer-1651484

Matt, I think I stated the problem clearly in the beginning of this conversation. Again: the font size in my signature has shrunk since the latest Thunderbird update. I would like to know HOW to make the signature font size the same as the message font size.

Perhaps another description of the issue would be to say that since the most recent Thunderbird update the font size in my email messages has increased, while the font size in my signature has remained the same.

I know nothing about computer coding, but if the recent update changed the default message font size to LARGE, that might explain my issue with matching the message and signature font sizes. I've now discovered that when writing an email, if I got to Format > Size and then change the default Large to Medium, the message font size matches the signature font size.

If there is a way to change the default message font size to medium (or any other remedy) please let me know. I would really appreciate it.

That information was provided in detailed instructions to you. Follow them. You could not find Settings>composition, as I recall. See attached.