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';

   img10=new Image(0,0);
   img10.src='./images/degazage.gif';
   img11=new Image(0,0);
   img11.src='./images/oxydation.gif';
   img12=new Image(0,0);
   img12.src='./images/filtration.gif';
   img13=new Image(0,0);
   img13.src='./images/regazage.gif';
   img14=new Image(0,0);
   img14.src='./images/degazage_r.gif';
   img15=new Image(0,0);
   img15.src='./images/oxydation_r.gif';
   img16=new Image(0,0);
   img16.src='./images/filtration_r.gif';
   img17=new Image(0,0);
   img17.src='./images/regazage_r.gif';
   img18=new Image(0,0);
   img18.src='./images/degazage_t.jpg';
   img19=new Image(0,0);
   img19.src='./images/oxydation_t.jpg';
   img20=new Image(0,0);
   img20.src='./images/filtration_t.jpg';
   img21=new Image(0,0);
   img21.src='./images/regazage_t.jpg';
   img22=new Image(0,0);
   img22.src='./images/vide.jpg';

	document.description.src = './images/vide.jpg';
}

function rollDegazage() {
	document.description.src = './images/degazage_t.jpg';
	document.degazage.src = './images/degazage_r.gif';
}

function unrollDegazage() {
	document.description.src = './images/vide.jpg';
	document.degazage.src = './images/degazage.gif';
}

function rollOxydation() {
	document.description.src = './images/oxydation_t.jpg';
	document.oxydation.src = './images/oxydation_r.gif';
}

function unrollOxydation() {
	document.description.src = './images/vide.jpg';
	document.oxydation.src = './images/oxydation.gif';
}

function rollFiltration() {
	document.description.src = './images/filtration_t.jpg';
	document.filtration.src = './images/filtration_r.gif';
}

function unrollFiltration() {
	document.description.src = './images/vide.jpg';
	document.filtration.src = './images/filtration.gif';
}

function rollRegazage() {
	document.description.src = './images/regazage_t.jpg';
	document.regazage.src = './images/regazage_r.gif';
}

function unrollRegazage() {
	document.description.src = './images/vide.jpg';
	document.regazage.src = './images/regazage.gif';
}