WordPress前端上传问题

在前端，我创建了一个表单，该表单使用upload_user_file()从正面主题上传文件，并且每个图像都很好地存储在WordPress媒体库中（看起来是这样）。

因此，当我上传名为test.jpg的文件时，将创建其相对缩略图并在媒体库中可见。测试-150x150.jpg测试-300x225.jpg测试-1024x768.jpg

我遇到的问题是当我从媒体库中删除此图像时。仅删除创建的缩略图，上传文件夹中test.jpg保持不变。如果我直接从媒体库上传此文件，然后将其删除，则删除所有文件，包括test.jpg.

下面是将值存储在数据库中并将文件上传到媒体库的代码。有没有另一个WordPress功能可以使用？我想upload_user_file()没有将图像数据正确存储在数据库中？

global $wpdb;
global $post;
//$table = 'wp_verk1_project'; //$post_slug=$post->post_name;
$table = $wpdb->prefix . "project_name_" . $post_slug=$post->post_name;
$data = array(
    'contributorname' => $_POST['yourname'],
    'email' => $_POST['email'],
    'telephone' => $_POST['telephone'],
    'description' => $_POST['description'],
    'date' => date('Y-m-d'),
    'time' => date('H:i:s'),
    'upload' => upload_user_file($_FILES['file']),
    'upload2' => upload_user_file($_FILES['file2']),
    'upload3' => upload_user_file($_FILES['file3']),
    'upload4' => upload_user_file($_FILES['file4']),
    'upload5' => upload_user_file($_FILES['file5']),
    'rate' => '0'
);
$format = array(
    '%s',
    '%s'
);
$success = $wpdb->insert($table, $data, $format);
if ($success) {
    header("Location: " . get_bloginfo('url') . "/thank-you/");
    exit();
}

edit_user_file（）：

function upload_user_file( $file = array() ) {
    require_once( ABSPATH . 'wp-admin/includes/admin.php' );
    $file_return = wp_handle_upload( $file, array('test_form' => false ) );
    if( isset( $file_return['error'] ) || isset( $file_return['upload_error_handler'] ) ) {
        return false;
    } else {
        $filename = $file_return['file'];
        $attachment = array(
            'post_mime_type' => $file_return['type'],
            'post_title' => preg_replace( '/'.[^.]+$/', '', basename( $filename ) ),
            'post_content' => '',
            'post_status' => 'inherit',
            'guid' => $file_return['url']
        );
        $attachment_id = wp_insert_attachment( $attachment, $file_return['url'] );
        require_once (ABSPATH . 'wp-admin/includes/image.php' );
        $attachment_data = wp_generate_attachment_metadata( $attachment_id, $filename );
        wp_update_attachment_metadata( $attachment_id, $attachment_data );
        if( 0 < intval( $attachment_id ) ) {
            return $attachment_id;
        }
    }
    return false;
}

亲切问候Johan