Thunderbird

From: https://kb.mozillazine.org/Privacy_basics_-_Thunderbird

To modify your exceptions list:

This used to add an entry to the address book that had either "Allow remote content" or "Allow remote images in HTML mail" checked for the specific sender. Recent versions store this information in permissions.sqlite and content-prefs.sqlite instead. You can modify that information using Tools -> Options -> Privacy -> Mail Content -> Exceptions.<

If you can not see any remote images check that View -> Message Body As is set to "Original HTML". "Simple HTML" and "Plain Text" do not show remote images. <

To allow all content (this is a bad idea, but whatever I'm comment not a cop)

Its possible to display all images from any sender, though its not recommended since malware can be embedded in images, and spammers will be able to verify your e-mail address. If you want to do this use the Config editor to toggle the preference mailnews.message_display.disable_remote_image to false.<

A better alternative would be to use the Config editor to create a mail.trusteddomains setting that specifies what e-mail domains it should automatically display remote images for. This is much easier than having to specify each email address, but you're taking the risk that you won't get any messages with a spoofed From: header in one of those domains. The setting contains a list of domains separated by commas, with no wild cards, white space or subdomains allowed. This change won't take effect until you restart Thunderbird. <