.hero .hero-media {
    /* Été */
  background-image:url(//s3.amazonaws.com/imagescloud/images/ct/amc/20160401-m.jpg);
  /* Hiver */
   /* background-image:url(//s3.amazonaws.com/imagescloud/images/ct/amc/20141205-m.jpg);*/
}

@media only screen and (min-width: 768px) {
  .hero .hero-media {
    /* Été */
    background-image:url(//s3.amazonaws.com/imagescloud/images/ct/amc/20160401.jpg);
  /* Hiver */
    /*background-image:url(//s3.amazonaws.com/imagescloud/images/ct/amc/20141205.jpg);*/

  }
}