<?php
/**
 图片压缩操作类
 v1.0
*/
   class Image{
       
       private $src;
       private $imageinfo;
       private $image;
       public  $percent = 0.1;
       public function __construct($src){
           
           $this->src = $src;
           
       }
       /**
       打开图片
       */
       public function openImage(){
           
           list($width, $height, $type, $attr) = getimagesize($this->src);
           $this->imageinfo = array(
                
                'width'=>$width,
                'height'=>$height,
                'type'=>image_type_to_extension($type,false),
                'attr'=>$attr
           );
           $fun = "imagecreatefrom".$this->imageinfo['type'];
           $this->image = $fun($this->src);
       }
       /**
       操作图片
       */
       public function thumpImage(){
           
            $new_width = $this->imageinfo['width'] * $this->percent;
            $new_height = $this->imageinfo['height'] * $this->percent;
            $image_thump = imagecreatetruecolor($new_width,$new_height);
            //将原图复制带图片载体上面，并且按照一定比例压缩,极大的保持了清晰度
            imagecopyresampled($image_thump,$this->image,0,0,0,0,$new_width,$new_height,$this->imageinfo['width'],$this->imageinfo['height']);
            imagedestroy($this->image);    
            $this->image =     $image_thump;
       }
       /**
       输出图片
       */
       public function showImage(){
           
            header('Content-Type: image/'.$this->imageinfo['type']);
            $funcs = "image".$this->imageinfo['type'];
            $funcs($this->image);
           
       }
       /**
       保存图片到硬盘
       */
       public function saveImage($name){
           
            $funcs = "image".$this->imageinfo['type'];
            $funcs($this->image,$name.'.'.$this->imageinfo['type']);
           
       }
       /**
       销毁图片
       */
       public function __destruct(){
           
           imagedestroy($this->image);
       }
       
   }
 

?>

测试

<?php  
          
        require 'image.class.php';  
        $src = "001.jpg";  
        $image = new Image($src);  
        $image->percent = 0.2;  
        $image->openImage();  
        $image->thumpImage();  
        $image->showImage();  
        $image->saveImage(md5("aa123"));  
  
  
?>

原文：
http://blog.csdn.net/gaoxuaiguoyi/article/details/49592151