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

复制代码 代码如下:

<?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