.login h1 a {
  background-image:none;
  display:none;
}
.login h1 {
  background-image: url('http://www.cp-productions.fr/wp-content/themes/cptheme/woomedias/logo-cp.png');
/*  background-size:contain; */
  background-position:50% 50%;
  background-repeat:no-repeat;
  height:100px;
}