BuddyPress.org

Add this to your bp-custom.php file:

function tj_add_default_avatar( $url )

{

return get_stylesheet_directory_uri() .'/_inc/images/avatar.jpg';

}

add_filter( 'bp_core_mysteryman_src', 'tj_add_default_avatar' );

You might have to adjust the path and/or change the image name.

EDIT: Oops, just realized you wanted to change the group avatar. I’ll have a look…