In my version (Linux, 38.6.0) it's in Preferences. Do you have a three-bar symbol to the right of the Search bar? Click on that and Preferences should be an option.

No Preferences is not an option. Thanks

You do not see this when you open the Options window?

I do not see that or the calendar.

This is what my options box looks like.

Are you using a very old version of Thunderbird because several things look different in your image ? What version are you using ?

Done a bit of digging to locate info on very old versions: If you previously allowed emails from a particular contact to always allow remote content to be shown: click on 'Address Book' select the address book to see list contacts. double click on contact to open the 'Edit contact' window. At bottom you will see 'Allow Remote content' checkbox. If it is selected, then all emails from that person will show remote content. Uncheck the checkbox if you want to start blocking - not allowing any remote content to be displayed from that person.

click on OK see image below.

I just downloaded it two days ago. How do I know if it's the latest version?

Under the Help Menu. About Thunderbird. Right where it is in all software.

I'm not sure where you dowloaded from, but it is an old version. The official download page is here, where you can select suitable download for language and OS: https://www.mozilla.org/en-US/thunderbird/all/

Thank you!

Glad to hear all is now ok. If my comment starting Done a bit of digging to locate info resolved the issue, could you mark that comment as 'Chosen Solution'. Then if someone has a similar issue they can locate an answer more easily.