Sorry for the delayed response.
Kindly follow the steps —
1.Pls modify file custom-post-types.php (framework/presentation/custom-post-types.php) line no:255 to –
'supports' => array('title', 'thumbnail', 'excerpt', 'custom-fields')
2.In the gallery Edit page enter a custom field named mo_url to the name field and give the desired link to the value field.
3. Insert following code in thumbnail-functions.php (framework/functions/thumbnail-functions.php)line no:114
$gallery_url = get_post_meta(get_the_ID(), 'mo_link', true);
Also modify line no:132 to –
$image_info .= '';