Niccasio "Dynamic Headers" not functioning

After creating the folder header-images (writable-775) in wp/content and adding the php code in the RtPanel theme /Header.php file (tried multiple insertion points as no recommendation for location provided)'<?php if(function_exists(‘show_media_header’)){ show_media_header(); } ?>’ and created a new page containing the uploaded media file I want as the header, and inserting the short code,none of my layouts are visible in the panel on the right side “site layout customer” screen. I’d truly be grateful for any help on this plug in. I’m working with the theme RtPanel. Thanks.