Php 调整相同图像的大小2次

我上传了一个php脚本的图像，我想能够改变图像的大小，如果图像太大，然后创建一个拇指相同的图像，现在我的图像大小调整，但拇指没有创建的原因…没有错误。 以下是脚本：

        if($image_data['image_width'] > 1024 || $image_data['image_height'] > 768)
      {


    $config_resize = array(
            'source_image' => $image_data['full_path'],
            'new_image' => "./uploads/",
            'overwrite' => true,
            'maintain_ratio' => true,
            'width' => 1024,
            'height' => 768
            );
     $this->load->library('image_lib', $config_resize);
     if(! $this->image_lib->resize())
       {
         echo $this->image_lib->display_errors();
       }


    $config_thumb = array(
        'source_image' => $config_resize['source_image'],
        'new_image' => "./uploads/thumbs/",
        'maintain_ratio' => true,
        'width' => 150,
        'height' => 100
        );
    $this->load->library('image_lib', $config_thumb);

    if(! $this->image_lib->resize())
       {
         echo $this->image_lib->display_errors();
       }


      }

。。。。。
.....  
$config\u thumb=数组(
'source_image'=>$config_resize['source_image']，
“新建图像”=>“/uploads/thumbs/”，
“保持_比率”=>true，
“宽度”=>150，
“高度”=>100
);
$this->image\u lib->initialize（$config\u thumb）//
.....
.....  

    $config_thumb = array(
                'source_image' => $config_resize['source_image'],
                'new_image' => "./uploads/thumbs/",
                'maintain_ratio' => true,
                'width' => 150,
                'height' => 100
                );

$this->image_lib->initialize($config_thumb); // <--- !!!