在wordpress中添加前端的特征图像

Question

我们如何在前端WordPress的自定义帖子类型中添加功能图像。任何人都可以帮忙吗？我尝试过，但没有得到正确的结果。请帮忙。

 <?php
 if ( isset( $_POST['submitted'] ) && isset( $_POST['post_nonce_field'] ) && wp_verify_nonce( $_POST['post_nonce_field'], 'post_nonce' ) ) {
 global $wpdb;
    if ( trim( $_POST['postTitle'] ) === '' ) {
        $postTitleError = 'Please enter a title.';
        $hasError = true;
    }

    $post_information = array(
        'post_title' => wp_strip_all_tags( $_POST['postTitle'] ),
        'post_content' => $_POST['postContent'],
        'post_type' => 'stories',
        'post_status' => 'publish'
    );

 echo  $post_id =  wp_insert_post( $post_information );
    if ($_FILES) {
array_reverse($_FILES);
$i = 0;//this will count the posts
foreach ($_FILES as $file => $array) {
    if ($i == 0) $set_feature = 1; //if $i ==0 then we are dealing with the first post
    else $set_feature = 0; //if $i!=0 we are not dealing with the first post
    $newupload = insert_attachment($file,$pid, $set_feature);
    echo $i++; //count posts
    }
    }
 }
 ?>

<div class="mid-wrapper">

<form action="" id="primaryPostForm" method="POST">

    <fieldset>
        <label for="postTitle"><?php _e('Post Title:', 'framework') ?></label>

        <input type="text" name="postTitle" id="postTitle" class="required" />
    </fieldset>

    <fieldset>
        <label for="postContent"><?php _e('Post Content:', 'framework') ?></label>

        <textarea name="postContent" id="postContent" rows="8" cols="30" class="required"></textarea>
    </fieldset>
 <label for="file">Filename:</label>
<input type="file" name="file" id="file"><br>

    <fieldset>
        <input type="hidden" name="submitted" id="submitted" value="true" />
 <?php wp_nonce_field( 'post_nonce', 'post_nonce_field' ); ?>
        <button type="submit"  name="submitted"><?php _e('Add Post', 'framework') ?></button>
    </fieldset>

</form>

</div>  

我们如何在前端WordPress的自定义帖子类型中添加功能图像。任何人都可以帮忙吗？我尝试过，但没有得到正确的结果。请帮忙。