phpパッケージの画像（サムネイル）の処理の完全な例

<?php
//       
class Image{
    //  
    private $thumb_width; //     
    private $thumb_height;
    //    
    public $thumb_error;
    //    
    public function __construct($width = 0,$height = 0){
      $this->thumb_width = ($width == 0) ? $GLOBALS['config']['admin_goods_thumb']['width'] : $width;
      $this->thumb_height = ($height == 0) ? $GLOBALS['config']['admin_goods_thumb']['height'] : $height;
    }
    /*
     *      
     * @param1 string $src，    ，/uploads/20150122101010abcdef.gif
     * @param2 string $path，       /uploads/thumb_20150122101010abcdef.gif
     * @return       
    */
    public function makeThumb($src,$path){
      //        
      if(!file_exists($src)){
        $this->thumb_error = '     ！';
        return false;
      }
      //      
      //         
      $ext = $this->getFunctionName($src); //gif
      //     
      $open = 'imagecreatefrom' . $ext;    //imagecreatefromgif
      $save = 'image' . $ext;          //imagegif
      //     ；echo $open,$save;exit;
      //          
      $src_img = $open($src); //            
      //imagecreatefromgif($src)
      //     
      $dst_img = imagecreatetruecolor($this->thumb_width,$this->thumb_height);
      //       
      $dst_bg_color = imagecolorallocate($dst_img,255,255,255);
      imagefill($dst_img,0,0,$dst_bg_color);
      //       
      $dst_size = $this->thumb_width / $this->thumb_height;
      //      
      $file_info = getimagesize($src);
      $src_size = $file_info[0]/$file_info[1];
      //        
      if($src_size > $dst_size){
        //          
        $width = $this->thumb_width;
        $height = round($width / $src_size);
      }else{
        $height = $this->thumb_height;
        $width = round($height * $src_size);
      }
      //         
      $dst_x = round($this->thumb_width - $width)/2;
      $dst_y = round($this->thumb_height - $height)/2;
      //     
      if(imagecopyresampled($dst_img,$src_img,$dst_x,$dst_y,0,0,$width,$height,$file_info[0],$file_info[1])){
        //    ：  ，            
        $thumb_name = 'thumb_' . basename($src);
        $save($dst_img,$path . '/' . $thumb_name);
        //    
        return $thumb_name;
      }else{
        //    
        $this->thumb_error = '       ！';
        return false;
      }
    }
    /*
     *            
     * @param1 string $file，    
     * @return                
    */
    private function getFunctionName($file){
      //       
      $file_info = pathinfo($file);
      $ext = $file_info['extension']; //  ：gif,png,jpg,jpeg,pjpeg
      //imagecreatefromgif,imagecreatefromjpeg,imagecreatefrompng
      //           
      $func = array(
        'gif' => 'gif',
        'png' => 'png',
        'jpg' => 'jpeg',
        'jpeg' => 'jpeg',
        'pjpeg' => 'jpeg'
      );
      //   
      return $func[$ext];
    }
}