Image-crop-center

gistfile1.txt

a {
  display: block;
  width: 200px;
  height: 200px;
  overflow: hidden;
  margin: 10px;
  position: relative;
  border: solid 1px #353535;
}

img {
    position:absolute;
    left: -100%;
    right: -100%;
    top: -100%;
    bottom: -100%;
    margin: auto;
    min-height: 100%;
    min-width: 100%;
}

img-html

<a>
  <img class="img-thumb" 
       src="https://s-media-cache-ak0.pinimg.com/236x/3a/ef/64/3aef64b6678201ef4e4d8e5b5007f96e.jpg"
       >
</a>
<a>
  <img class="img-thumb" 
       src="https://s-media-cache-ak0.pinimg.com/236x/e4/c9/82/e4c982a64d6870b904721a4737339172.jpg"
       >
</a>
<a>
  <img class="img-thumb" 
       src="https://s-media-cache-ak0.pinimg.com/736x/f4/56/6d/f4566dfded2bb9abeacbe42feb8a7c2d.jpg"
       >
</a>
<a>
  <img class="img-thumb" 
       src="http://pre04.deviantart.net/9e90/th/pre/i/2013/068/4/3/lia__manga_by_sophie__chan-d5xgpu2.jpg"
       >
</a>