To diagnose problems with Thunderbird, try the following:

• Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.
• Restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.

Ok, gave it a try (had already tried TBird safe mode to no avail) but tried again. No success. Went to Win safe mode, no success, both in safe mode, nothing.

Tried going backwards to version 27, 26, 20 no change. Ever since the update to 38 the ability to see remote content is just plain gone. Is there a TBird version of about:config that I can play with settings in?

There is. Config Editor

Can't see anything out of the expected. Any clues that I should be looking for? I have tried all of the safe modes. I have moved backwards in the releases of T-Bird to the 20s, I have run MalwareBytes, SuperDuperClean this thing out ware, even combofix, there has been no change in behavior, my remote content is still blank. All Firewalls down, nuthin. Oh sages of the ether, help me please! I beseech thee.

the most obvious question. What mail clients are your mails coming from?

Make sure the View menu (alt+V)>"message body as..." is set to Original HTML. if you save the email as a HTML file. and open it in your browser do the remote images appear then?

Server is an old straight up pop server. I have checked the view setting, no changes. Of note, I did a complete removal of TBird last night and an install of version 10. I left the profiles in place and the problem was still there. I then did a complete removal again and moved the profile to a different directory and reinstalled 10. The remote images are no showing properly so it is in the profile that something is amiss. The question is which file has the bomb in it. I will continue to play with it until I find the issue or reestablish whatever normal is.

Correction to spelling issue above, after moving the profile the remote content was visible. I have copied the old mail directory to the current profile and all of my emails are there and the remote content shows correctly so the mail folder did not contain the problem. Also, I tried the save as HTML on two emails to see if that worked and it tried to open about a dozen tabs in Firefox when I tried to view it so that was glitchy. Even when it is told to save as html, it shows as an eml in the directory, that happened on several attempts.