Broken images tend to mean the image contains remote content and by default Thunderbird blocks remote content. See info: https://support.mozilla.org/en-US/kb/remote-content-in-messages

Sorry but this did not solve the issue. Enabled the remote content in privacy settings as suggested but still the same. I do not get the "remote content in this message" bar in the message. in the settings advanced the email address is set to "allow"

Thanks for the suggestion

re :I do not get the "remote content in this message" bar in the message.

You will not see the yellow message To protect your privacy, Thunderbird has blocked remote content in this message below headers but above message if:

• Email was marked as junk and is currently in the Junk/Spam folder.
• If you had previously allowed that email address to display remote content.
• If you have the Settings > Privacy & Security - 'allow remote content in messages' selected.

I would suggest you see if resetting everything allows you to get the yellow message banner back. I'm assuming the email is not in the Junk/spam folder.

Try this:

• Menu icon > Settings > Privacy & Security

'Mail Content' section

• Do Not select/uncheck the checkbox: 'allow remote content in messages'
• click on 'exceptions..' button
• Select the email address
• click on 'Remove site'
• click on 'Save changes'

• Menu icon > Settings > General
• Scroll down to 'Disk Space' section
• click on 'Clear now' button

Exit Thunderbird - wait a few moments then Start Thunderbird.

Did you get the yellow banner displaying again ?

Remote content won't be displayed if View/Message Body As is anything else than Original HTML.

Got the banner back, Selected all (2) above, Still the same

re :Selected all (2) above, That sounds like you are switching display all remote from all sites no matter if they are invading rivacy etc. The idea was to get the yellow banner back and then reset via that banner and leave the auto remote switched off.

Please repeat the actions in previous comment to reset.

Once you get the yellow banner back which contains 'Options' button You need to use that 'Options' button. click on 'Options' and select the last option in the list which should allow from that email address. Then report on whether all the icons now display in that email.

Please tell me what Anti-Virus product you are using. I have known Avast Shield to cause issues.

OK re-did it. Still the same.

I use Avast Free Antivirus, not sure if that is the same as Avast Shield.

OK, I tried disabling/pausing Avast. Restarted Tbird. Still the same.

UN-installed Avast Reset Banner.

Still same issue.