functions.php

<?php

add_action( 'genesis_after_header', __NAMESPACE__ . '\\output_slider' );
/**
 * Output our slider component after the header.
 * 
 * @since 1.0.0
 */
function output_slider() {

	$post_id    = get_the_ID();
	$image_ids  = get_post_meta( $post_id, 'project_header_slider', true );
	$slide_urls = [];

	foreach ( $image_ids as $image_id ) {
		$slide_urls[] = wp_get_attachment_image_url( $image_id, 'large' );
	}

	// Pass array of slide URLs.
	wp_localize_script( 'project', 'urls', $slide_urls );

	// Add short inline script to initialize Backstretch.js on .slider.
	wp_add_inline_script(
		'project',
		'// <![CDATA[
			 jQuery(\'.slider\').backstretch(urls, { duration: 6000, fade: 1000 });
		// ]]>'
	);

	do_action( 'project_before_slider' );
	include locate_template( 'views/slider.php' );
	do_action( 'project_after_slider' );

}