var default_img;
var default_width;

visite=new Image(); visite.src="../images/visite_76x50.jpg";
matrimoni=new Image(); matrimoni.src="../images/matrimonio_72x50.jpg";
scolaresche=new Image(); scolaresche.src="../images/animazioni_32x50.jpg";
conferenze=new Image(); conferenze.src="../images/conferenze_80x50.jpg";

function change_img(img_name) {
    default_img=document.left_img.src;
    default_width=document.left_img.width;
    new_src=eval (img_name + ".src");
    document.left_img.width=eval (img_name + ".width");
    document.left_img.src=new_src;
}
function clear_img(img_name) {
    document.left_img.src=default_img;
    document.left_img.width=default_width;
}