n*n Image View

.image-wall-wrapper{
  font-size: 0;
}
.image-wall-wrapper .image-item{
  display: inline-block;
  background-size: cover;
  background-repeat: no-repeat;
  /*25% is for 4*4*/
  width: 25%;
  /*padding-top has the same value to width*/
  padding-top: 25%;
  /*background is within padding*/
  background-clip: padding-box;
  /* be center*/
  background-position: 50%;
  /* the margin between image and image*/
  border-bottom: 4px solid transparent;
  border-left: 4px solid transparent;
  /* border is calculated into width*/
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  background-image: url(http://qzonestyle.gtimg.cn/aoi/sola/20141222185945_O20XHGAoR2.jpg)
}