Background gallery query

// WP_Query arguments
$args = array (
	'post_type'              => 'gallery',
	'category_name'          => 'background_gallery',
	'pagination'             => true,
	'posts_per_page'         => '1',
	'orderby'                => 'rand',
	'cache_results'          => false,
	'update_post_meta_cache' => false,
	'update_post_term_cache' => false,
);

// The Query
$bg_gallery = new WP_Query( $args );

// The Loop
if ( $bg_gallery->have_posts() ) {
	while ( $bg_gallery->have_posts() ) {
		$bg_gallery->the_post();
		// do something
	}
} else {
	// no posts found
}

// Restore original Post Data
wp_reset_postdata();