I had the exact same thing happen last week and it took me days to work out the problem then days more to fix it. It seems I had a trojan (I have Mozilla Firefox 1.04)and I had trouble getting PCCillin to pick it up. Even with the latest updates. I ran Ad-Aware SE Personal and it deleted the extras the trojan left but I had trouble deleting the trojan itself. It had embedded itself in the browser cache of both IE and Firefox so I emptied the cache of both, reinstalled Firefox and any images that wouldn't load, I hunted for the cached page and used that. It fixed it. And I know nothing about technical stuff so I surprised myself that I'd actually managed to fix it. It works fine now. Some of my gallery images weren't loading which triggered the hunt for the problem. Don't know if this solution will help anyone else but I thought it was worth mentioning.