var chemin = "images/";

var ext = ".png";

var liste_images = new Array('bt1_maqu_r','bt2_maqu_r','bt3_maqu_r','bt4_maqu_r','bt5_maqu_r','bt6_maqu_r','bt7_maqu_r');

document.image_chargee = new Array();

window.onload=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;

}

}