// if the post has a featured image, send it to Backstretch else use a default one
if ( has_post_thumbnail() ) {
	wp_localize_script( 'backstretch-init', 'BackStretchImg', array( 'src' => wp_get_attachment_url( get_post_thumbnail_id() ) ) );
}
else {
	wp_localize_script( 'backstretch-init', 'BackStretchImg', array( 'src' => 'http://genesis.dev/wp-content/themes/genesis-sample/images/picjumbo.com_IMG_6533-1600.jpg' ) );
}