BuddyPress.org

I’m creating a child theme fo bp. I like to use an other image than default mystery man. How can i do this? I think i’m missing something.

This is what i put in the function.php but it doesn’t work

function konax_core_set_avatar() {
define( ‘BP_AVATAR_DEFAULT’, get_stylesheet_directory_uri() . ‘/images/mystery-man.jpg’ );
define( ‘BP_AVATAR_DEFAULT_THUMB’, get_stylesheet_directory_uri() . ‘/images/mystery-man-50.jpg’ );
}

any other idea for the theme is appreciate. here is the link http://quicktesting.tk/members/admin/