.parent{

  width:300px;

  position: relative;

  padding-top: 50%;

}

​

.parent .inner{

  position:absolute;

  top:0;

  left:0;

}

​

.parent img{

  width:100%;

  height:100%;

  /*position:absolute;

  top:0;

  left:0;

  right:0;

  bottom:0;

  margin: auto;*/

}