add_filter(
	'sp_wpcp_image_attachments',
	function( $attachments, $post_id ) {
		// replace 2727 with your shortocde id 
		if ( '2727' === $post_id && class_exists( 'WooCommerce' ) ) {
			global $product;
			if( ! is_object( $product ) ){
				return $attachments;
			}
			$gallery     = array();
			$gallery_ids = $product->get_gallery_image_ids();
			$image_id    = $product->get_image_id();

			if ( empty( $gallery ) ) {
				if ( $image_id ) {
					array_push( $gallery, $image_id );
				}
				if ( $gallery_ids ) {
					$gallery = array_merge( $gallery, $gallery_ids );
				}
			}
			$attachments = $gallery;
		}
		return $attachments;
	},
	10,
	2
);