// 将源文件剪切全部域并缩小放到目标图片上。前两个为资源句柄

imagecopyresampled(

$thumb

, 

$source

, 0, 0, 0, 0, 

$newwidth

, 

$newheight

, 

$width

, 

$height

);

// 输出给浏览器

imagejpeg(

$thumb

);

?>
 

 

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：
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);