$user = user_load($user->uid);
$account = user_load($user->uid);
print theme(
    'image_style',
    array( 'account' =>$user,
      'style_name' => 'x-small',
     // 'path' =>!empty($user->picture->uri)?$user->picture->uri:variable_get('user_picture_default'),
      'path' =>!empty($user->picture->uri)?$user->picture->uri:variable_get('user_picture_default',''),
      'attributes' => array(
        'class' => 'avatar'
      )
    )
  );