Nice simple plugin, it did not have support for the exclude parameter.
I added it by doing the following, for post thumbnail featured image.
In simple-scrollbar-gallery.php
replace the lines 99-101 with the following;
$exclude = get_post_thumbnail_id( $post->ID. 'thumbnail' );
extract(shortcode_atts(array(
'order' => 'ASC',
'orderby' => 'menu_order ID',
'id' => $post->ID,
'exclude' => $exclude,
), $attr));
$id = intval($id);
$attachments = get_children( array('post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby, 'exclude' => $exclude) );http://wordpress.org/extend/plugins/simple-scrollbar-gallery/
