How to display users Gravatar image?

Many users have images on Gravatar. If you want to dispaly user’s Gravatar image then you just need email address of that user and get its MD5 hash then append it to Gravatar URL. Following is example.

   $gravatar_url = 'http://www.gravatar.com/avatar/' . md5($user_email_address) . '?s=32';
   echo '<img src="' . $gravatar_url . '" width="32" height="32" />';