fredriklind

This worked for me:

add_filter( 'bawmrp_no_thumb', 'change_bawmrp_no_thumb', 10, 2);
function change_bawmrp_no_thumb( $thumb, $post_id) {
	return 'http://altijara.net/wp-content/themes/al-tijara/images/Al-Tijara-logo-footer.png';
}

I also had to change the number of related posts displayed in settings to see the change. I guess it’s cached.