<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>
<nav class="navbar navbar-default" role="navigation">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#dropdown-thumbnail-preview">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Brand</a>
</div>
<div class="collapse navbar-collapse" id="dropdown-thumbnail-preview">
<ul class="nav navbar-nav">
<li class="active"><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li class="dropdown thumb-dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">My Snippets <span class="caret"></span></a>
<ul class="dropdown-menu" role="menu">
<li role="presentation" class="dropdown-header">Simple thumbnail</li>
<li>
<a href="#">
Preview carousel indicators
<div class="thumbnail">
<img class="img-responsive" src="http://krowdly.co/snippets/thumbnails/1.jpg">
</div>
</a>
</li>
<li>
<a href="#">
