IMAGE01 = "images/bullite.gif"  
IMAGE02 = "images/blank.gif"
IMAGE03 = "images/bullite_blue.gif"  
function imgover(imgname){
     imgname.src = IMAGE01
}

function imgout(imgname){
     imgname.src = IMAGE02
}

function imgover_blue(imgname){
     imgname.src = IMAGE03
}

function imgout_blue(imgname){
     imgname.src = IMAGE02
}