@media only screen and (min-width: 768px) and (max-width: 1023px) {
  img {width:100%;height:100%;}
}

@media only screen and (min-width: 480px) and (max-width: 767px) {
  img {width:100%;height:100%;}
}

@media only screen and (min-width: 320px) and (max-width: 479px) {
  img {width:100%;height:100%;}
}

@media only screen and (max-width: 320px) {
  img {width:100%;height:100%;}
}