Images Don't Display Right

When I go to several sites with IE7 most of the images don't display, no matter what format they're saved in. The images work when I use Firefox but I'm really reluctant to switch because some of my HTML goods don't work with Firefox and those are really nice to have around. The problem started soon after I installed an update of some sort and I don't know how to uninstall them. What can I do to remedy this situation?

Thanks,
Sylvia