So I have a question regarding a custom function I'm using on a Divi child theme to pull/display the Featured Image for any given page on the site. It actually works, but a problem has arisen where, when I make a change on a page that is calling this function and then save, it returns the following error: Warning: Attempt to read property "ID" on null in /home/customer/www/example.com/public_html/wp-content/themes/Divi-child/functions.php on line 30 Warning: Cannot modify header information - headers already sent by (output started at /home/customer/www/example.com/public_html/wp-content/themes/Divi-child/functions.php:30) in /home/customer/www/example.com/public_html/wp-admin/post.php on line 231 However, it saves properly and works when I reload the public-facing page. But like I said, it goes to a white page with this error on the back every time now when I save/preview and it makes me have to hit the back button to get to the edit page screen. This happens on both PHP 8 and 8.1. Is there a simple change I can make to the following code to fix this issue? ------------------------------------------- // ADD SHORTCODE TO DISPLAY FEATURED IMAGE function display_featured_image_shortcode($atts) { global $post; $default_atts = array( 'size' => 'thumbnail', // default image size 'class' => '', // default CSS class for the image ); $atts = shortcode_atts($default_atts, $atts, 'featured_image'); if (has_post_thumbnail($post->ID)) { $featured_image = get_the_post_thumbnail($post->ID, $atts['size'], array('class' => $atts['class'])); return $featured_image; } else { return ''; // return empty string if there's no featured image } } add_shortcode('featured_image', 'display_featured_image_shortcode'); I tried changing PHP versions as I don't know anything else to try. Thanks in advance!