Fatalkeyv, another user who was reporting this issue just notified me that he had discovered the source of the problem. He was using the Firefox extension PrefBar, which gives you the option to disable the sending of referral information (the address of the page which is requesting an image). If you have this extension installed, please try disabling this feature and you should be able to see the images.
No, PrefBar is an extension that might cause the problem for you, not fix it, so you can uninstall that if you want. While you're doing that, please try disabling all of your extensions in Firefox, then hit refresh on the homepage and see what happens.