big-bgs.php

<?php
/**
* Full-size Backgrounds using a Post Type of Background
*
* Function that selects a custom post type 'background'.
* Uses the Post Thumbnail as the background image.
* On the Page template(s) where it's needed, call s25_full_bg.
*
*/
function s25_full_bg() {
 // Build loop arguments for selecting Background
	if ( !wp_is_mobile() ) {
		$bgargs = array (
			'post_status' => 'publish',
			'post_type' => 'background',
			'orderby' => 'menu_order',
			'posts_per_page' => 7,
		);

		// Loop that grabs a Background
		$bg_loop = new WP_Query( $bgargs );
		if ( $bg_loop->have_posts() ) {
			echo '<div id="bg_full">';
			while ( $bg_loop->have_posts() ) : $bg_loop->the_post();
				// Selects the post thumbnail from the Background and sets it as the fixed, full-width background image.
				if ( has_post_thumbnail() ) {
					$thumb = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'full' );
					$obg_img = $thumb['0'];
				}

			echo '<div class="bg"><img src="'. $obg_img .'" alt="" /></div>';

			endwhile;
			echo '</div><!-- close .bg_full -->';
		}
	wp_reset_postdata();
	}

}
add_action ( 'genesis_before_header','s25_full_bg' );