this shows how to swap out an image using CSS only. theoretically, the w3c hints at it being possible using url(). but in actuality, it does not work on ANY browser.
the cookies should change by hovering over them. they don't.
this is purely css, and some of this stuff I am using is simply css2.1 which never got implemented by ANY browser. I guess nobody ever thought a person would want to swap out an image using CSS. w3c did. they hinted at it in their standard.
you could just as well use js to modify the images if you wanted.