我有一个问题，提交自定义后，从前端与图像。我有一个带有帖子标题、描述和图片的表单，应该是帖子的特色图片。因此，当用户提交帖子时，它实际上创建了标题和描述，但没有图像，即使在媒体库中，图像也不会出现。Here is my form:

<form id="_themename-advert-create-form" method="post" enctype="multipart/form-data">
    <?php wp_nonce_field(\'_themename_submit_advert_action\',\'__themename_submit_advert_nonce\'); ?>
    <input type="hidden" name="_themename-advert-create-check" value="1" />
    
    <label for="_themename-advert-create-title">Title</label>
    <input id="_themename-advert-create-title" type="text" name="_themename-advert-create-title" />

    <label for="_themename-advert-create-content">Sample Content</label>
    <textarea id="_themename-advert-create-content" rows="8" name="_themename-advert-create-content"></textarea>

    <label for="_themename-advert-create-image">Upload Post Image</label>
    <input type="file" id="_themename-advert-create-image" name="_themename-advert-create-image" />

    <input type="submit" id="_themename-advert-create-submit" value="SUBMIT" name="_themename-advert-create-submit" />

</form>

Here is my function that creates custom post:

add_action(\'init\', \'_themename_create_new_post\');
function _themename_create_new_post(){
    
    if(\'POST\' == $_SERVER[\'REQUEST_METHOD\'] && isset($_POST[\'_themename-advert-create-check\']) && wp_verify_nonce( $_POST[\'__themename_submit_advert_nonce\'], \'_themename_submit_advert_action\')) {
        $current_user = wp_get_current_user();
        $user_id = $current_user->ID;

        $new_post_title = sanitize_text_field($_POST[\'_themename-advert-create-title\']);
        $new_post_content = sanitize_textarea_field($_POST[\'_themename-advert-create-content\']);

        $new_post = array();
        $new_post[\'post_author\'] = $user_id;
        $new_post[\'post_title\'] = $new_post_title;
        $new_post[\'post_content\'] = $new_post_content;
        $new_post[\'post_status\'] = \'pending\';
        $new_post[\'post_name\'] = \'pending\';
        $new_post[\'post_type\'] = \'jana_usa\';

        $post_success = wp_insert_post($new_post);
        
        if ( $_FILES ) { 
            $files = $_FILES["_themename-advert-create-image"];  
            foreach ($files[\'name\'] as $key => $value) {
                if ($files[\'name\'][$key]) {
                    $file = array( 
                        \'name\' => $files[\'name\'][$key],
                        \'type\' => $files[\'type\'][$key], 
                        \'tmp_name\' => $files[\'tmp_name\'][$key], 
                        \'error\' => $files[\'error\'][$key],
                        \'size\' => $files[\'size\'][$key]
                    );
                    $_FILES = array ("_themename-advert-create-image" => $file);
                    foreach ($_FILES as $file => $array) {              
                        // $newupload = frontend_handle_attachment( $file, $post_success );
                        if ($_FILES[$file][\'error\'] !== UPLOAD_ERR_OK) __return_false();

                        require_once(ABSPATH . "wp-admin" . \'/includes/image.php\');
                        require_once(ABSPATH . "wp-admin" . \'/includes/file.php\');
                        require_once(ABSPATH . "wp-admin" . \'/includes/media.php\');

                        $attach_id = media_handle_upload( $file, $post_success );

                        // Set featured image 
                        set_post_thumbnail($post_success, $attach_id);
                    }
                }
            }
        }

    }

}

foreach ($files[\'name\'] as $key => $value) { ...