var chemin = "images/";
var ext = ".jpg";
var liste_images = new 

Array('cepesc_on','livre_on','commander_on','liens_on','contacr_on','cepesc2_on','livre2_on','commander2_on','liens

2_on','contacr2_on');
document.image_chargee = new Array();
function prechargement() {
for ( i = 0; i < liste_images.length; i++ ) {
document.image_chargee[i] = new Image;
document.image_chargee[i].src = chemin + liste_images[i] + ext;
}
}