var imgvec = new Array("http://www.vanityfair.com/images/ontheweb/2007/02/wear01_autumn0702.jpg", "http://www.vanityfair.com/images/ontheweb/2007/02/wear02_autumn0702.jpg");

function toggle(source, imgsrc1, imgsrc2)
{
if(source.src == imgvec[imgsrc1])
{
source.src = imgvec[imgsrc2];
return;
}

source.src = imgvec[imgsrc1];
}