我不得不生成一堆额外的代码，因为我不认为您已经发布了所有代码。在这种情况下，我没有脚本来添加库，所以我通过在帖子中提取库数据来填充元框来测试它。每个标题文本字段是根据图像生成的，然后在保存后更新。

这将显示元框和库中的每个图像，每个图像带有标题和两个按钮。更改标题文本将在保存时设置图像的post\\u摘录。

function mytheme_show_post_gallery_metabox($post) {

    wp_nonce_field(\'mytheme_post_gallery_metabox\', \'_mytheme_post_gallery_metabox\');
    $gallery = get_post_meta($post->ID, \'_mytheme_post_gallery\', true);

    // START | TESTING
    // pull the gallery images from all galleries if it hasn\'t been created
    if(empty($gallery)) {
        $galleries = get_post_galleries($post, false);
        $allIds = array();
        foreach($galleries as $data) {
            $ids = $data[ \'ids\' ];
            $ids = explode(\',\', $ids);
            $allIds = array_unique ( array_merge( $allIds, $ids ) );
        }
        $gallery = $allIds;
    }
    // END | TESTING ?>

    <style>
        ul#gallery-metabox-list li {
           float: left;
           margin-right: 5px;
        }
    </style>

    <a class="gallery-add button media-button button-primary button-large media-button-select" href="#"
       data-uploader-title="<?php _e(\'Add gallery images\', \'mytheme\'); ?>"
       data-uploader-button-text="<?php _e(\'Add gallery images\', \'mytheme\'); ?>"><?php _e(\'Add gallery images\', \'mytheme\'); ?></a>
    <table>
        <tr>
            <td>
                <ul id="gallery-metabox-list">
                    <?php if($gallery) : ?>
                        <?php foreach($gallery as $key => $value) :
                            $image = wp_get_attachment_image_src($value);
                            $image_id = $value;
                            $image_post = get_post($image_id);
                            $caption = $image_post->post_excerpt;
                            ?>
                            <li>
                                <input type="hidden" name="_mytheme_post_gallery[<?php echo $key; ?>]"
                                       value="<?php echo $value; ?>">
                                <img class="image-preview" src="<?php echo $image[ 0 ]; ?>">
                                <p>
                                    <label for="_mytheme_caption_text_<?php echo $image_id; ?>"
                                           class="mytheme-row-title"><?php _e(\'Caption\', \'mytheme\') ?></label>
                                    <input type="text" name="_mytheme_caption_text_<?php echo $image_id; ?>"
                                           id="_mytheme_caption_text_<?php echo $image_id; ?>"
                                           value="<?php echo $caption; ?>"/>
                                </p>
                                <p>
                                    <a class="change-image" href="#"><?php _e(\'Change\', \'mytheme\'); ?></a> | <a
                                        class="remove-image" href="#"><?php _e(\'Remove\', \'mytheme\'); ?></a>
                                </p>
                            </li>
                        <?php endforeach; ?>
                    <?php endif; ?>
                </ul>
            </td>
        </tr>
    </table>
    <?php
}

设置元框

add_action(\'add_meta_boxes\', \'myplugin_add_meta_box\');

function myplugin_add_meta_box() {

    $screens = array(\'post\', \'page\');

    foreach($screens as $screen) {

        add_meta_box(
            \'myplugin_sectionid\',
            __(\'My Post Section Title\', \'mytheme\'),
            \'mytheme_show_post_gallery_metabox\', // meta box view
            $screen
        );
    }
}

保存时，更新库并提取ID。对于每个ID，检查并查看post数据中是否有标题文本字段。如果存在，则更新图像的帖子内容。

add_action(\'save_post\', \'mytheme_save_image_gallery_metabox\');

function mytheme_save_image_gallery_metabox($post_id) {

    // see: http://themefoundation.com/wordpress-meta-boxes-guide/

    if( ! isset($_POST[ \'_mytheme_post_gallery\' ]) || ! wp_verify_nonce($_POST[ \'_mytheme_post_gallery_metabox\' ], \'mytheme_post_gallery_metabox\')) return;
    if( ! current_user_can(\'edit_post\', $post_id)) return;
    if(defined(\'DOING_AUTOSAVE\') && DOING_AUTOSAVE) return;
    if(isset($_POST[ \'_mytheme_post_gallery\' ])) {
        $gallery = wp_kses($_POST[ \'_mytheme_post_gallery\' ], \'\');
        update_post_meta($post_id, \'_mytheme_post_gallery\', $gallery);
        foreach($gallery as $image_id) {
            if( ! is_numeric($image_id)) continue; // not a number, not an ID
            if(isset($_POST[ \'_mytheme_caption_text_\' . $image_id ])) {
                $caption = $_POST[ \'_mytheme_caption_text_\' . $image_id ];
                $caption = wp_kses($caption); // clean it up
                // change the image caption
                wp_update_post(array(\'ID\' => $image_id, \'post_excerpt\' => $caption));
            }
        }
    }
    else {
        delete_post_meta($post_id, \'_mytheme_post_gallery\');
    } 
}