function changeImage1(){
 document.index1.src="img/to_mid_button_over.gif";
}
function changeImage2(){
 document.index1.src="img/to_mid_button_out.gif";
}

function changeImage3(){
 document.index2.src="img/to_alb_button_over.gif";
}
function changeImage4(){
 document.index2.src="img/to_alb_button_out.gif";
}