WordPress generate new size for old posts

auto-regenerate-thumb.php

<?php
require_once(ABSPATH . 'wp-admin/includes/image.php');

// Put the function in a class to make it more extendable
class KRS_regen_media
{
    public function krs_regenerate($imageId)
    {
        $imagePath = wp_get_original_image_path($imageId);

        if ($imagePath && file_exists($imagePath)) {
            $attach_data = wp_generate_attachment_metadata($imageId, $imagePath);
            return wp_update_attachment_metadata($imageId,  $attach_data);
        } else {
            return "File not exist";
        }
    }
}

// Add a load function
function krs_regen_load()
{
    if (isset($_GET['thumb-regenerate'])) {
        $regenerateThumb = sanitize_text($_GET['thumb-regenerate']);
        if ($regenerateThumb == '1') {
            $uploads_directory = wp_upload_dir();
            $all_posts = get_posts(array(
                'fields' => 'ids',
                'numberposts' => -1
            ));
            echo '<pre>';
            $generateImage = [];
            $generateImageFail = [];
            foreach ($all_posts as $postId) {
                $imageId = get_post_thumbnail_id($postId);
                if ($imageId != 0) {
                    $am = wp_get_attachment_image_url($imageId, 'size-card');
                    if (!preg_match('/(-720x405)/', $am)) {
                        // Instantiate the class
                        $krs_regen_media = new KRS_regen_media();
                        // You can get the image Id from the url of the media screen
                        $regenerate = $krs_regen_media->krs_regenerate($imageId);
                        if ($regenerate != 'File not exist' && $regenerate !== false) {
                            $generateImage[] = [
                                'id'        => $imageId,
                                'image'     => $am,
                            ];
                        } else if ($regenerate == 'File not exist') {
                            $generateImageFail[] = [
                                'id'        => $imageId,
                                'image'        => 'File not exist',
                            ];
                        }
                        // thumbnail_cleaner_rmdir($uploads_directory['basedir']);
                    } else {
                        $generateImage[] = [
                            'id'        => $imageId,
                            'image'     => $am,
                        ];
                    }
                }
            }
            $result = [
                'post_count'                => count($all_posts),
                'total_success'   => count($generateImage),
                'total_failed'    => count($generateImageFail),
                'generate'                  => array_merge($generateImage, $generateImageFail),
            ];

            print_r(json_encode($result));
        }
        die();
    }
}

// Load after WordPress has finished loading
add_action('init', 'krs_regen_load');

function thumbnail_cleaner_rmdir($directory)
{
    $objects = (array)scandir($directory);
    foreach ($objects as $object) {
        if ($object !== "." && $object !== "..") {
            if (filetype($directory . "/" . $object) === "dir") {
                thumbnail_cleaner_rmdir($directory . "/" . $object);
            } else {
                // Remove unused file thumbnail
                if (preg_match('/(.webp)/', $object)) {
                    unlink($directory . "/" . $object);
                }
            }
        }
    }
}