<link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<html>
<head>
<title>Rollover with a Mouse Events</title>
<script type="text/javascript">
if(document.images){
var image1 = new Image(); // Preload an image
image1.src = "https://pbs.twimg.com/profile_images/741523114278916096/7bL6w5dy.jpg";
var image2 = new Image(); // Preload second image
image2.src = "http://suvenconsultants.com/mainpagefiles/images/training.jpg";
}
</script>
</head>
<body>
<p>Move your mouse over the image to see the result</p>
<a href="#" onMouseOver="document.myImage.src=image2.src;" onMouseOut="document.myImage.src=image1.src;">
<img name="myImage" style="width:200px;height:200px;" src="https://pbs.twimg.com/profile_images/741523114278916096/7bL6w5dy.jpg" />
</a>
</body>
</html>