I wish this worked properly for updating status bar images. It does in Netscape (at least the older versions I tested it on), but IE does odd things with half of the image swaps and only finishes swapping them when the page completes. Danged buggy browser :(

You can see if it works on your browser version here:
http://www.home-school.com/cgi-local/update.pl

It's supposed to update the bar by 1% every 3 seconds.