Everything that Dan posts above is true... but the fact that the images do show for other users (as posted by mkrausnick) leads me to think there might be another reason.
Maybe the cache on your browser is full (I'm assuming Windows with IE -- since that's the most popular combo). You could confirm this by testing in another browser (Firefox)... if the images show, then it's most likely the cache.
To clear the temporary files in IE for Windows:
Select "Internet Options" from the "Tools" menu. Inside the area titled "Temporary Internet Files" click the "Delete Files" button and delete the temprary cache files. Then try visiting the page again.
Cheers,
Jeff