kevmatic

Try this:

$post_id = $_GET['post'] ? $_GET['post'] : $_POST['post_ID'] ;
 // Only Show the Metabox on the Home Page - ID = 4
    if ($post_id == '4')
	{
	new MultiPostThumbnails(
		array(
		     'label' => 'Homepage Feature Left',
		     'id' => 'home-feature-left',
	             'post_type' => 'page'
		)
	);
    }