Click the site favicon ( How do I know if my connection to a Web site is secure?) on the left end of the address bar.
Open the web page that has the missing images in a browser tab.
You can use the following steps to check if the images are blocked:
Check exceptions in tools > Options > content: Load Images > Exceptions (for example sphotos.ak.).
If you select that right click menu context then you block all images from this area and not a specific image, so do not use that. I was able to view them in the browser, so it's something I've done in Firefox. I was on facebook and remove an icon by using the right-click menu, but then all my photos and pictures of profile, could no longer be seen.