<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<header id="header2">
<div class="box"></div>
<h2 class="caption">Summer</br>Collection</h2>
<img src="http://www.pngall.com/wp-content/uploads/2016/05/Model-PNG-HD.png" class="" alt="">
<button class="btn btn-light action">Call to Action</button>
</header>