.hero .hero-media {
  /* Été */ 
  background-image:url(//s3.amazonaws.com/imagescloud/images/pq/gas/20150311-m.jpg);
  /* Automne *//*
background-image:url(//s3.amazonaws.com/imagescloud/images/pq/gas/20150901-m.jpg);
/* Hiver*/
/* background-image:url(//s3.amazonaws.com/imagescloud/images/pq/gas/20141205-m.jpg); */
}

@media only screen and (min-width: 768px) {
  .hero .hero-media {
    /* Été */
  background-image:url(//s3.amazonaws.com/imagescloud/images/pq/gas/20150311.jpg);
  /* Automne *//*
background-image:url(//s3.amazonaws.com/imagescloud/images/pq/gas/20150901.jpg);
/* Hiver*/
/* background-image:url(//s3.amazonaws.com/imagescloud/images/pq/gas/20141205.jpg);*/
  }
}