In previous versions of Mail on macOS, there was an entry in Settings that read "Load remote content in messages".
I'd like to disable loading remote content. Is that possible to do in Catalina, either via the GUI or via the command line?
Mail on macOS Catalina – Disable ‘Load Remote Content in Messages’
mail.appprivacy
Related Solutions
osascript -l JavaScript -e 'Application("Mail").inbox.unreadCount()'
This uses Mail's unified inbox to display the number of unread messages, thus, it's equal to the number on Mail's red icon badge.
First, make sure Mail's junk mail filtering is enabled in Mail preferences under Junk Mail.
Messages marked as "Junk" in Mail (orange-tinted, with the 
icon) will automatically not display remote content, even if "Load remote content in messages" is turned on in Mail preferences! If Mail automatically detected a message to be junk, the following banner will be displayed:
However, if a message arrives that Mail doesn't think is Junk, this leaves you with a problem: if you view the message to mark it as junk, the remote content will be loaded. To mark a message as junk without loading it, right-click it in the message list and click Mark > As Junk Mail.
Now if you view it, it will show this banner instead of loading remote content:
Best Answer
From https://support.apple.com/en-in/guide/mail/cpmlprefview/13.0/mac/10.15
This is found in