function change_images( no ){ 
max = 16;
img_file = "./images/scenes/image"+String(no)+".jpg";
document.getElementById("img_b").src = img_file;
document.getElementById("img_b").src = img_file;

no_new = no+1;
if ( no_new > max ) no_new = 1;
setTimeout("change_images( no_new )", 4000);
return;
}