Setup a loop in php to get your array of values and then echo those values inside of backstretch or other js functions. Below is an example of using PODS to pull a marquee image from a CPT created with Pods. While you can use php directly inside your script tag, the js functionality will not work properly; for instance, in the case of Backstretc…

backstretch and dynamic images

<?php
  	$counter = 0;
		$marqueesParams = array('limit'=> 20);
		$marquees = pods('marquee');
		$marquees->find($marqueesParams);
		if (0 < $marquees->total()){
			while ($marquees->fetch()) {
				
				$artwork = $item->field('marquee_artwork');
	                        foreach($artwork as $art) {
                        	   $artwork_js .= "\"".$art['guid']."\", ";
                        	}
		    
			}
		}
	 ?>
	<script>jQuery(document).ready(function($){
		$.backstretch([<?=$artwork_js?>], {duration: 13000, fade: 750});
	});
	</script>