We can use different mask to style an image.
Using the Bootstrap built-in classes we can style images with the round cornered or circular images, or give them effect like thumbnails.
<!DOCTYPE HTML>
<html>
<head>
<link href="http://java2s.com/style/bootstrap.min.css" rel="stylesheet">
</head><!-- w w w .j a va2s .c om-->
<body style='margin:20px;'>
<img src="http://java2s.com/style/download.png" class="img-rounded">
<img src="http://java2s.com/style/download.png" class="img-circle">
<img src="http://java2s.com/style/download.png" class="img-thumbnail">
</body>
</html>