var pictures = new Array               
    ("images/random/!.gif",
     "images/random/button.gif",
     "images/random/cloud.gif",
     "images/random/coffee.gif",
     "images/random/corrado_8bit.gif",
     "images/random/corrado_fencing.gif",
     "images/random/corrado_hat.gif",
     "images/random/corrado_messy.gif",
     "images/random/corrado_yawn.gif",
     "images/random/feather.gif",
     "images/random/question.gif"
    );

function random() {
    var node = document.getElementById("random-image")
    var random = Math.floor((Math.random()*pictures.length));
    if (node != null) node.src = pictures[random];
}