No, red X's means your browser can't find those pictures. It could be because they don't exist, or your setup is preventing it from finding them or even blocking them.

Now, if everyone here can't see the pictures, then it's a server error.

If only those who have specific software settings to block them, then it's due to those software and/or settings.

I test the forum with a combination of about 10 or so different versions of browsers, and different computers, and they all work fine. The only browsers I can't check are Mac browsers, because I don't have a Mac machine.

So the most likely reason is that you are blocking cookies. Some may not even be aware of it, but have their browsers or other software block them.

Wa'il