Yes, you can do this. I have an extremely convoluted system that displays transparent graphics depending on which browser version is being run. For the browsers that support it, you get the nice alpha-transparent PNGs. For the browsers that barely support it (there is an intermediate version of IE that could do transparent PNG if you called the right directX graphics library and also feed it a blank transparent GIF as a background image) it does the needful. For browsers that don't support it at all, it shows the crappy hard-edged GIF.

It all uses the IE feature of conditional comments. You make comments with the "IF IE" tag and then certain versions of IE render them. I had to do it with a bunch of DIV's to make it work for all browsers.

It's all there at www.vixyandtony.com , do a "View Source" on the main root index page or the Music page. (The other pages don't need the special code because the cartoons don't intersect the top bar of trees.)