Issue #2313085 by tkuldeep17: Can't add class to user picture by template_preprocess_user_picture as class attribute has hard coded in user picture tpl file

CHANGELOG.txt

@@ -1,6 +1,8 @@
 
 Drupal 7.40, xxxx-xx-xx (development version)
 -----------------------
+- Allowed the user-picture.tpl.php theme template to have HTML classes besides
+  the default "user-picture" class printed in it (markup change).
 - Fixed the URL text filter to convert e-mail addresses with plus signs into
   mailto: links.
 - Added alternate text to file icons displayed by the File module, to improve

modules/user/user-picture.tpl.php

@@ -17,7 +17,7 @@
  */
 ?>
 <?php if ($user_picture): ?>
-  <div class="user-picture">
+  <div class="<?php print $classes; ?>">
     <?php print $user_picture; ?>
   </div>
 <?php endif; ?>