img = new Array();

img[0] = "img/image02.jpg";
img[1] = "img/image03.jpg";
img[2] = "img/image08.jpg";
img[3] = "img/image09.jpg";
img[4] = "img/image10.jpg";
img[5] = "img/image11.jpg";
img[6] = "img/image-sakamoto.jpg";

n = Math.floor(Math.random()*img.length);

document.write("<img src='"+img[n]+"' border='0' alt='' />");