goodtrunk=new Image(269, 206);
badtrunk=new Image(269, 206);

goodtrunk.src="images/nicesttrunk.jpg";
badtrunk.src="images/beatesttrunk.jpg";

function swaptrunk()
{
document.images["imgmain"].src = goodtrunk.src;
}

function backagain()
{
document.images["imgmain"].src = badtrunk.src;
}