Showing default avatar in Friends:mine

Question

I am trying to show a default avatar if the member hasnt uploaded a custom avatar.

Here is my code:

{exp:friends:mine reciprocal="y" orderby="screen_name" sort="asc" limit="5" member_group_id="6" member_id="{segment_3}" dynamic="no"}
<li class="network">
  {if friends_avatar_url}
  <a href="{path='volunteers/profile'}/{member_id}/">
    {exp:ce_img:single src="{friends_avatar_url}" width="50" height="50" }
    {friends_screen_name}
  </a>
  {if:else}                  
  <a href="{path='volunteers/profile'}/{member_id}/">
    <img src="{site_url}images/avatars/default_set/default-member-ph.png" width="50" height="50">
    {friends_screen_name}
  </a>
  {/if}
</li>

{if friends_no_results}
<li class="noresults">No Volunteers</li>
{/if}{/exp:friends:mine}

Is there a reason why the conditional wouldn't work?