Images set to not load - crashes IE9 and FFox 17 on forum sites

I posted about this before, but I didn't ask the question - WHY?

On this laptop (Win 7 enterprise x64, intel i5 2.4G quad core and 4G RAM)
I have images set to not load right now. Sevenforums seems to be behaving fine. But I won't try this on 1000RR.net or Watchuseek or Fireblades.org. Within seconds, the amount of images "trying" to load, and my setting to block them, causes a total freeze of the browser and eventually I have to kill it in Tsk-Tsk-Tsk Mgr.

You can see the processor is trying way too hard for a page that's not supposed to be showing anything other than ads without pictures, and text. And it is FFox that's responsible for the load, I looked.

So someone who really understands the inner workings of the advertising conspiracy, tell me... why can't I turn off images on a forum page without it crashing my browser?

With all the ads on those forums, they're my first choice for using this switch. And with a few keystrokes in FFox 17.1 (alt+t, o, tick/untick the box, enter) I can effectively switch image load on and off without too much of a hassle. But God help me if I forget they're off and I go to a forum. I think I tried this while Javascript was turned off too, but no matter what the result, I like the auto-fill and other automations Java provides.