I noticed that I am getting the alt string rather than the icon for being a subscribed to a thread. So I took a look at the http source to find the URL for the gif. It's http://www.head-case.org/forums/images/misc/subscribed.gif. When trying to view the gif directly with that URL, I get a File Not Found error. Since everything else is working for me, I assume that something has happened to this link. Is anything wrong there?

I can see it fine. Checkmark, right?

works here

Since nobody else had posted about it, I thought that I might be the only one. So I tried it with, cough, IE. It worked there. I tried killing and restarting all my Firefox instances and nothing changed. So I rebooted and, voila, it's working now. So somehow Firefox decided it was a bad URL and mucked with it or ...? Anyway, now it works for me.

You probably marked it for offline reading. :\