With Facebook on display, click on the site identity button (for details on what that is see the site identity button article) and then on More Information. This will open up the page info dialog.

First select the Permissions panel, make sure that "Load Images" is set to allow (selecting Use Default should also work)

Next select the Media panel, then click on the first item in the list. Use the down arrow key to scroll through the list. If any item has the option "Block images from (domain name)" selected, de-select the option.

This should hopefully resolve your issue, but also see Fix problems that cause images to not show.

Some add-ons can also block images, for example if you have AdBlock Plus installed, make sure that you have not accidentally created a filter to block the images.

I tried the identity thing and nothing happens. I assume I mistakenly clicked something on Firefox. But cannot figure out what it is.

Do you have any exceptions for images set?

• Check the permissions for the domain in the current tab in "Tools > Page Info > Permissions"
• Check that images are enabled: Tools > Options > Content: [X] Load images automatically
• Check the exceptions in "Tools > Options > Content: Load Images > Exceptions"
• Check the "Tools > Page Info > Media" tab for blocked images (scroll through all the images with the cursor Down key).

If an image in the list is grayed and there is a check-mark in the box "Block Images from..." then remove that mark to unblock the images from that domain.

There are also extensions (Tools > Add-ons > Extensions) and security software (firewall, anti-virus) that can block images.

• https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes