Get the WordPress attachment ID of an image from it's URL

get-image-id.php

/**
 * Get the attachment ID of an image from it's URL.
 *
 * @link https://pippinsplugins.com/retrieve-attachment-id-from-image-url/
 *
 * @param $image_url
 *
 * @return mixed
 */
function dmgist_get_image_id($image_url) {
	global $wpdb;
	$attachment = $wpdb->get_col($wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE guid='%s';", $image_url ));
	return $attachment[0];
}