<div class="container">

  <div class="element">
    <img src="http://tympanus.net/codrops-playground/assets/images/cssref/properties/mask-border-repeat/sleepy-owl.jpg" alt="">
  </div>
  <p><strong>You should read more about how the different border image properties work together in the <a href="http://tympanus.net/codrops/css_reference/mask-border"><code>mask-border</code></a> shorthand property entry</strong>.</p>
</div>

body {
  color: #555;
  font-size: 1.1em;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

.container {
  margin: 40px auto;
  max-width: 700px;
}

.element {
  border: 5px solid #ddd;
  -webkit-mask-border-source: url(http://tympanus.net/codrops-playground/assets/images/cssref/properties/mask-border-repeat/mask-border-image.png);
  mask-border-source: url(http://tympanus.net/codrops-playground/assets/images/cssref/properties/mask-border-repeat/mask-border-image.png);
  -webkit-mask-border-width: 27px;
  mask-border-width: 27px;
  -webkit-mask-border-slice: 27;
  mask-border-slice: 27;
  -webkit-mask-border-outset: 20px;
  mask-border-outset: 20px;
  -webkitmask-border-repeat: stretch;
  mask-border-repeat: stretch;
}

img {
  width: 100%;
  display: block;
}