Set Default Pinterest Share Image based on Featured Image

pinterest

<?php if ( has_post_thumbnail() ) :
 $src = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), array( 720,405 ), false, '' );
?>  
   <a href="http://pinterest.com/pin/create/button/?media=<?php echo $src[0]; ?>&url=<?php the_permalink() ?>" class="pin-it-button" count-layout="none"><img border="0" src="//assets.pinterest.com/images/PinExt.png" title="Pin It" /></a>
<?php else : ?>
   <a href="http://pinterest.com/pin/create/button/?media=http://example.com/example.png&url=<?php the_permalink() ?>" class="pin-it-button" count-layout="none"><img border="0" src="//assets.pinterest.com/images/PinExt.png" title="Pin It" /></a>
<?php endif; ?>