img = new Array();
img[0] = "./images/image/01.jpg";
img[1] = "./images/image/02.jpg";
img[2] = "./images/image/03.jpg";
img[3] = "./images/image/04.jpg";
img[4] = "./images/image/05.jpg";
n = Math.floor(Math.random()*img.length);
document.write("<img src='"+img[n]+"' />");