<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <!------ Include the above in your HEAD tag ----------> <div> <div class="row no-gutters"> <div class="col-md-4"> <div> <img src="https://cdn.pixabay.com/photo/2015/04/23/22/00/tree-736885__480.jpg"/> </div> </div> <div class="col-md-4"> <div> <img src="https://cdn.pixabay.com/photo/2015/04/23/22/00/tree-736885__480.jpg"/> </div> </div> <div class="col-md-4"> <div> <img src="https://cdn.pixabay.com/photo/2015/04/23/22/00/tree-736885__480.jpg"/> </div> </div> </div> </div>

div { background-color: red; border:1px solid black; } img { width: 100%; height: auto; }