function ChangeImage(id) {

var contenu;

   if (id==1)  {
     contenu ="<img class='photo-agence' src='Photos/photo-agence1.jpg' alt='photo-agence1.jpg' /><ul><li><a href='javascript:ChangeImage(1);'><img src='Photos/photo-agence1-small.jpg' /></a></li><li><a href='javascript:ChangeImage(2);'><img src='Photos/photo-agence2-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(3);'><img src='Photos/photo-agence3-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(4);'><img src='Photos/photo-agence4-small-w.jpg' /></a></li></ul>";
   }
   if (id==2)  {
    contenu ="<img class='photo-agence' src='Photos/photo-agence2.jpg' alt='photo-agence2.jpg' /><ul><li><a href='javascript:ChangeImage(1);'><img src='Photos/photo-agence1-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(2);'><img src='Photos/photo-agence2-small.jpg' /></a></li><li><a href='javascript:ChangeImage(3);'><img src='Photos/photo-agence3-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(4);'><img src='Photos/photo-agence4-small-w.jpg' /></a></li></ul>";
   }
   if (id==3)  {
    contenu ="<img class='photo-agence' src='Photos/photo-agence3.jpg' alt='photo-agence3.jpg' /><ul><li><a href='javascript:ChangeImage(1);'><img src='Photos/photo-agence1-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(2);'><img src='Photos/photo-agence2-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(3);'><img src='Photos/photo-agence3-small.jpg' /></a></li><li><a href='javascript:ChangeImage(4);'><img src='Photos/photo-agence4-small-w.jpg' /></a></li></ul>";
   }

   if (id==4)  {
    contenu ="<img class='photo-agence' src='Photos/photo-agence4.jpg' alt='photo-agence4.jpg' /><ul><li><a href='javascript:ChangeImage(1);'><img src='Photos/photo-agence1-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(2);'><img src='Photos/photo-agence2-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(3);'><img src='Photos/photo-agence3-small-w.jpg' /></a></li><li><a href='javascript:ChangeImage(4);'><img src='Photos/photo-agence4-small.jpg' /></a></li></ul>";
   }

   document.getElementById('bloc-photos-agence').innerHTML = contenu;

}