var images = new Array();

images[1] = "images/random/1.jpg";
images[2] = "images/random/2.jpg";
images[3] = "images/random/3.jpg";
images[4] = "images/random/4.jpg";
images[5] = "images/random/5.jpg";
images[6] = "images/random/6.jpg";
images[7] = "images/random/7.jpg";
images[8] = "images/random/8.jpg";

document.write('<img src='+images[Math.round((8*Math.random()+0.5))]+' width="560" height = "260" />');