wordPress 如何保存插件中上传的图片到对应插件的目录下面？

// Check that the nonce is valid, and the user can edit this post.
if (
    isset($_POST['my_image_upload_nonce'], $_POST['post_id'])
    && wp_verify_nonce($_POST['my_image_upload_nonce'], 'my_image_upload')
    && current_user_can('edit_post', $_POST['post_id'])
) {
    // The nonce was valid and the user has the capabilities, it is safe to continue.

    // These files need to be included as dependencies when on the front end.
    require_once(ABSPATH . 'wp-admin/includes/image.php');
    require_once(ABSPATH . 'wp-admin/includes/file.php');
    require_once(ABSPATH . 'wp-admin/includes/media.php');

    // Let WordPress handle the upload.
    // Remember, 'my_image_upload' is the name of our file input in our form above.
    $url=WPWSL_PLUGIN_URL . '/img/' . $imageSize . '.png';
//    update_option('upload_path',WP_CONTENT_DIR.'/uploads');
    update_option('upload_path',WPWSL_PLUGIN_URL.'/img/');
    $attachment_id = media_handle_upload('my_image_upload', $_POST['post_id']);

    if (is_wp_error($attachment_id)) {
        // There was an error uploading the image.
        echo "<p>There was an error uploading your file.</p>";
    } else {
        // The image was uploaded successfully!
        echo "<p>The image was uploaded successfully!</p>";
        add_filter('img', $attachment_id);
//        add_filter('img', 'custom_upload_directory');
    }

} else {
    echo "<p>The security check failed, maybe show the user an error</p>";
    // The security check failed, maybe show the user an error.

}

 <td>
                    <input type="file" name="my_image_upload" id="my_image_upload" multiple="false"/>
                    <input type="hidden" name="post_id" id="post_id" value="55"/>
                    <?php wp_nonce_field('my_image_upload', 'my_image_upload_nonce'); ?>
                    <input id="submit_my_image_upload" name="submit_my_image_upload" type="submit" value="Upload"/>

// Check that the nonce is valid, and the user can edit this post.
if (
    isset($_POST['my_image_upload_nonce'], $_POST['post_id'])
    && wp_verify_nonce($_POST['my_image_upload_nonce'], 'my_image_upload')
    && current_user_can('edit_post', $_POST['post_id'])
) {
    // The nonce was valid and the user has the capabilities, it is safe to continue.

    // These files need to be included as dependencies when on the front end.
    require_once(ABSPATH . 'wp-admin/includes/image.php');
    require_once(ABSPATH . 'wp-admin/includes/file.php');
    require_once(ABSPATH . 'wp-admin/includes/media.php');

    // Let WordPress handle the upload.
    // Remember, 'my_image_upload' is the name of our file input in our form above.
    $url=WPWSL_PLUGIN_URL . '/img/' . $imageSize . '.png';
//    update_option('upload_path',WP_CONTENT_DIR.'/uploads');
    update_option('upload_path',WPWSL_PLUGIN_URL.'/img/');
    $attachment_id = media_handle_upload('my_image_upload', $_POST['post_id']);

    if (is_wp_error($attachment_id)) {
        // There was an error uploading the image.
        echo "<p>There was an error uploading your file.</p>";
    } else {
        // The image was uploaded successfully!
        echo "<p>The image was uploaded successfully!</p>";
        add_filter('img', $attachment_id);
//        add_filter('img', 'custom_upload_directory');
    }

} else {
    echo "<p>The security check failed, maybe show the user an error</p>";
    // The security check failed, maybe show the user an error.

}

 <td>
                    <input type="file" name="my_image_upload" id="my_image_upload" multiple="false"/>
                    <input type="hidden" name="post_id" id="post_id" value="55"/>
                    <?php wp_nonce_field('my_image_upload', 'my_image_upload_nonce'); ?>
                    <input id="submit_my_image_upload" name="submit_my_image_upload" type="submit" value="Upload"/>