function BigPic(page,PicWidth,PicHeight)
{
var hauteur_popup=PicHeight;
var H = (screen.height - hauteur_popup) / 2;
var largeur_popup=PicWidth;
var L = (screen.width - largeur_popup) / 2;
pop_up = window.open(page,"Popup","status=no,scrollbars=no,resizable=no,height="+hauteur_popup+",width="+largeur_popup+",top="+H+",left="+L);
}