get acf gallery using post id outside of loop

gistfile1.txt

<?php
/*
    
    Created by craig@jucra.com on 22/7/2022
    
    The code below will get a list of photos in their
    order as they appear in the ACF gallery and provide
    you with the thumbnail and large versions.

    You can use $gallery to output the gallery code.
    
    You can also get the 1st main image.
    

*/
$images = get_post_meta( $post_id, "property_photos", $single = true );
$count = 0;
foreach($images as $img_id) {
    
    $img_thumb = wp_get_attachment_image_src($img_id, $size = 'thumbnail');
    $img_large = wp_get_attachment_image_src($img_id, $size = 'large');
    $image_total_text = "REF: $ecpt_referencenumber <br>Photo $image_number of $total_images";
    
    $gallery .= "
    <a href='".$img_large[0]."'>
        <img alt='".$image_total_text."' src='".$img_thumb[0]."'>
    </a>";
    
    //produce the main image
    if($count == 0) { $main_image = $img_large[0]; }
    
    $image_number = $image_number + 1;
    $count = $count + 1;

}