php生成缩略图的方法

<?php
/*
 * written by mot
 * 根目录下自己新建image thumb目录
 * */
class thumb{
  private $src;
  private $source;
  private $s_width;
  private $s_height;
  private $dest;
  private $d_height;
  private $d_width;
  private $name;
  public function thumb($image_path,$rate = 0.5){
    $this->src = $image_path;
    $this->source = imagecreatefromjpeg($image_path);
    $s_size = getimagesize($image_path);
    $this->s_height = $s_size[1];
    $this->s_width = $s_size[0];
    $this->d_height = 100;
    $this->d_width = 100;
    $this->dest = imagecreate($this->d_width, $this->d_height);
    $this->name = explode('.jpg', $image_path);
    $this->name = $this->name[0];
  }
  public function make(){
    imagecopyresized($this->dest, $this->source, 0, 0, 0, 0, $this->d_width, $this->d_height,
    $this->s_width, $this->s_height);
    $thumb = str_replace('image', 'thumb', $this->name.'-thumb.jpg');
    imagejpeg($this->dest,$thumb,100);
    $img = $thumb;
    echo "<a href=$this->src><img src=$img></a>";
  }
}
$hl = opendir(".\image\");
while(false != $file = readdir($hl)){
  if($file == '.' || $file == '..') continue;
  $path = '.\image\'.$file;
  $tmp = new thumb($path,0.3);
  $tmp->make();
}