设定宽高，不等比例缩放；设定宽度，等比例缩放；设定高度，等比例缩放；按比例，缩放至50%；缩放后直接输出到屏幕等等，具体使用方法如下，感兴趣的额朋友可以了解下哈

推荐一个简单实用的缩放图片工具 SimpleImage，参考http://www.white-hat-web-design.co.uk/blog/resizing-images-with-php/

使用方法：

设定宽高，不等比例缩放

 
<?php 
include('SimpleImage.php'); 
$image = new SimpleImage(); 
$image->load('picture.jpg'); 
$image->resize(250,400); 
$image->save('picture2.jpg');?> 

设定宽度，等比例缩放

<?php 
include('SimpleImage.php'); 
$image = new SimpleImage(); 
$image->load('picture.jpg'); 
$image->resizeToWidth(250); 
$image->save('picture2.jpg');?> 

设定高度，等比例缩放

<?php 
include('SimpleImage.php'); 
$image = new SimpleImage(); 
$image->load('picture.jpg'); 
$image->resizeToHeight(500); 
$image->save('picture2.jpg'); 
$image->resizeToHeight(200); 
$image->save('picture3.jpg');?> 

按比例，缩放至50%

<?php 
include('SimpleImage.php'); 
$image = new SimpleImage(); 
$image->load('picture.jpg'); 
$image->scale(50); 
$image->save('picture2.jpg');?>

缩放后直接输出到屏幕

<?php 
header('Content-Type: image/jpeg'); 
include('SimpleImage.php'); 
$image = new SimpleImage(); 
$image->load('picture.jpg'); 
$image->resizeToWidth(150); 
$image->output();?> 

SimpleImage.php 源码请轻点文章开头链接，到那下载