Jack,
When giving code to 4.1.x users, be aware that they had at one point, xhtml code that validated.
Using UPPER CASE <TABLE> and other html tags will immediately break the xhtml validation. I know that you are an expert coder in html, but xhtml has its benefits, and keeping a 4.1 store validating is always a good thing. Just thought I'd share.
Another way to accomplish this is to use css --
I would use the hr, but style it with css -- this way, you are not bringing in image calls on every page (multiple times at that!).
http://webdesign.about.com/od/css/a/aa010307.htm
New School is do not use images when you can use the local browser to do the work. CSS is your best friend.
Jeremy