Red x-again

I looked in the thread "Images Not displaying in internet explorer" in the frequently asked questions forum, but it did not solve my problem. Not all of the pictures show up as red x's, only some. An example of a few are on msn.com, and the front screen of yahoo.com. I first noticed this about a month or two ago. I've tried both Mozilla Firefox and Internet Explorer 6, but both gave the same frustrating results.
Any help would be greatly appreciated, Thanks. If you need more info, just ask.