php – Codeigniter缩略图图像路径无法存储在MySql中

我正在尝试使用Codeigniter创建一个简单的应用程序,我需要在 MySql数据库中存储缩略图图像路径.图像以及缩略图版本在上传文件夹中正确上传,我可以在上传时将图像路径存储在我的数据库中,但我无法将缩略图图像路径存储在数据库中.我在控制器中试过这个：

$thumbnail= $this->resize($data['upload_data']['full_path'],$data['upload_data']  ['file_name']);
$thumbnail_path = './uploads/'. $thumbnail;
$newRow = array(
                    "title" => $this->input->post('title'),"img_path" => $imgpath,"thumbnail_path" => $thumbnail_path,"post_body" => $this->input->post('post_body')
                    )

但它只在我的表格的thumbnail_path列中存储“./uploads/”,而不是实际的缩略图路径.我期望它存储类似“./uploads/Lighthouse_thumb.jpg”的东西.我无法弄清楚如何获取缩略图图像的路径以将它们存储在数据库中.这是我的完整上传控制器：
???????

class Upload extends CI_Controller
  {

function __construct()
{
    parent::__construct();
    $this->load->helper('form');    
}
function index() {

        $this->load->view('upload_form',array('error'=>''));
    }

function do_upload() {
    $config['upload_path'] = './uploads/';
    $config['allowed_types'] = 'gif|jpg|png';
    $config['max_size'] = '1000';
    $config['max_width']  = '1024';
    $config['max_height']  = '768';

    $this->load->library('upload',$config);

    if (!$this->upload->do_upload()) {
        $error = array('error' => $this->upload->display_errors());
        $this->load->view('upload_form',$error);
    } else {
        $image_data = $this->upload->data();
        $imgpath = './uploads/' . $image_data['file_name'];
        $data = array('upload_data'=>$this->upload->data());
        $thumbnail= $this->resize($data['upload_data']['full_path'],$data['upload_data']['file_name']);
        $thumbnail_path = './uploads/'. $thumbnail;
        $newRow = array(
                    "title" => $this->input->post('title'),"post_body" => $this->input->post('post_body')
                    );
            $this->load->model('postimage_path');
            $this->postimage_path->insert($newRow);
            $this->load->view('upload_success',$data);
    }

    }
function resize($path,$file) {
        $config['image_library'] = 'gd2';
        $config['source_image'] =  $path;
        $config['create_thumb'] = TRUE;
        $config['maintian_ratio'] = TRUE;
        $config['width'] = 100;
        $config['height'] = 100;
        $config['new_image'] = './uploads/' . $file;

        $this->load->library('image_lib',$config);
        $this->image_lib->resize();

    }

}

$thumbnail_path = './uploads/'. $thumbnail;

function resize($path,$file) {
    $config['image_library'] = 'gd2';
    $config['source_image'] =  $path;
    $config['create_thumb'] = TRUE;
    $config['maintian_ratio'] = TRUE;
    $config['width'] = 100;
    $config['height'] = 100;
    $config['new_image'] = './uploads/' . $file;

    $this->load->library('image_lib',$config);
    $this->image_lib->resize();

}

$pathinfo = pathinfo($data['upload_data']['file_name']);
 $thumbnail_path = './uploads/'. $data['upload_data']['file_name'] . "_thumb" . $pathinfo['extension'];