of course the window would have to be full size then.
the javascript solution would be:
<img src="../Meteora/quoterequest_files/header2.gif" border="0" onload="this.width = screen.width; this.height= screen.heght;">
or if you want to keep the aspect ratio just do it on the width (or swap width for height):
<img src="../Meteora/quoterequest_files/header2.gif" border="0" onload="this.width = screen.width;>
If you want to do this on many images, you could have a script function instead of putting the code in the images.