小编ved*_*har的帖子

body{
  background-image:url('http://i.telegraph.co.uk/multimedia/archive/03589/Wellcome_Image_Awa_3589699k.jpg');
}

.Image{
position:absolute;
  width:200px;
  height:200px;
}

.Image img{
  width:100%;
  height:100%;
}

.Image:before {
    position: absolute;
    content: "";
    border-top: 60px solid red;
    border-right: 60px solid transparent;
    top: -1px;
    left: -1px;
}
.Image:after {
    position: absolute;
    content: "";
    border-bottom: 60px solid red;
    border-left: 60px solid transparent;
    bottom: -1px;
    right: -1px;
}

.blackBg{
  position:absolute;
  top:0;
  left:0;
  width:100%;
  height:100%;
  background:rgba(0,0,0,0.6);
}

<div class="blackBg"></div>

<div class="Image">
  <img src="http://www.w3schools.com/css/img_fjords.jpg">
  </div>