<div class="container">

  
  
  <div class="row">
    <div class="col-md-6">
      <h2>Before</h2>
<img src="https://bootstrapcreative.com/wp-bc/wp-content/uploads/2016/11/pablo.png" width="400" />
    </div>
    <!-- /.col-md-6 -->
    <div class="col-md-6">
    <h2>After</h2>
<div class="img-gradient">
  <img src="https://bootstrapcreative.com/wp-bc/wp-content/uploads/2016/11/pablo.png" width="400" />
</div>
    </div>
    <!-- /.col-md-6 -->
  </div>
  <!-- /.row -->







  
  
</div>
/*
source
http://stackoverflow.com/a/23935891/3853728
*/

.img-gradient{
  position:relative;
  display:inline-block;
}


/* 
#002f4b,#dc4225 
Convert HEX to RGBA - http://hex2rgba.devoth.com/
*/
.img-gradient:after {
  content:'';
  position:absolute;
  left:0; top:0;
  width:100%; height:100%;
  display:inline-block;
  background: -moz-linear-gradient(top, rgba(0,47,75,0.5) 0%, rgba(220, 66, 37, 0.5) 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(220, 66, 37, 0.5)), color-stop(100%,rgba(0,47,75,0.5))); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(top, rgba(0,47,75,0.5) 0%,rgba(220, 66, 37, 0.5) 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(top, rgba(0,47,75,0.5) 0%,rgba(220, 66, 37, 0.5) 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(top, rgba(0,47,75,0.5) 0%,rgba(220, 66, 37, 0.5) 100%); /* IE10+ */
  background: linear-gradient(to bottom, rgba(0,47,75,0.5) 0%,rgba(220, 66, 37, 0.5) 100%); /* W3C */
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#002f4b', endColorstr='#00000000',GradientType=0 ); /* IE6-9 */
}
.img-gradient img{
  display:block;
}

External CSS

  1. https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css

External JavaScript

  1. //cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js
  2. //maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js