var theImages = new Array() 

theImages[0] = '1.jpg'
theImages[1] = '2.jpg'
theImages[2] = '3.jpg'
theImages[3] = '4.jpg'
theImages[4] = '5.jpg'

var j = 0
var p = theImages.length;
var preBuffer = new Array()
for (i = 0; i < p; i++){
   preBuffer[i] = new Image()
   preBuffer[i].src = theImages[i]
}
var whichImage = Math.round(Math.random()*(p-1));
function showImage(){
document.write('<a href="./accueil.php"><img src="_images/random_shared/'+theImages[whichImage]+'" border="0"></a>');
}