Originally Posted by Schturman

This my avatar block from IM css file, try it:

Code:

 * Avatars
 */
img.MessageAvatar { 
  width: 64px;
  height: 64px;
  outline-style: solid; 
  outline-width: 4px; 
  outline-offset: -1px; 
  -moz-outline-radius: 13px; 
  padding: 1px;
  vertical-align: middle; 
}

div.MessageAvatar { 
  width: 64px;
  height: 64px;
  -moz-border-radius: 10px; 
  border-width: 1px;
  border-style: solid;
  display: inline-block;
  vertical-align: middle;
}

Thanks to b666m