function preload() {

   img0=new Image(0,0);
   img0.src='./images/source.gif';
   img1=new Image(0,0);
   img1.src='./images/minerale.gif';
   img2=new Image(0,0);
   img2.src='./images/mineraux.gif';
   img3=new Image(0,0);
   img3.src='./images/source_r.gif';
   img4=new Image(0,0);
   img4.src='./images/minerale_r.gif';
   img5=new Image(0,0);
   img5.src='./images/mineraux_r.gif';
   img6=new Image(0,0);
   img6.src='./images/contact.gif';
   img7=new Image(0,0);
   img7.src='./images/contact_r.gif';
}