php有专门处理图片的函数，对于一些要求较高的图片缩放，php也能做到。

首先使用一个ini文件来设置要缩放的大小，其中为宽或高0的则为图片放大或缩小，都为0则还是原大小，都不为0都拉抻成指定的大小。

注意：ini文件使用php解释时为注释文件，什么也没有输出，这是为了安全起见而故意为之。而;则是ini文件的注释。

我设置的ini文件例子如下：

 
<?php 
/* 
;Translate the image format using the original image size 
[Translation] 
width=0 
height=0 

;Stretch the image to the specified size 
[Stretch] 
width=800 
height=600 

;Zoom the image to the specified Width with height auto size 
[AutoHeight] 
width=740 
height=0 

;Zoom the image to the specified Height with width auto size 
[AutoWidth] 
width=0 
height=380 
*/ 
?> 

下面是编写的缩放图片的php代码，其中变量classes是一个数组，可以选择任意多个ini文件中指定的设置：

 
<?php 
$oimg = "test.jpg";//Original image name 
$classes = array('Translation','AutoHeight','AutoWidth','Stretch');//Give classes for the new creating images' size which are defined in the specified ini file 
$suffix = 'jpg';//The new image's suffix 
$inifile = 'image.ini.php'; 

$size = getimagesize($oimg); 
$x = $size[0]/$size[1]; 
$name = explode('.',$oimg); 

if(!file_exists($inifile)) die('Ini file does not exist!'); 
$cn = parse_ini_file($inifile,true);//Parse the class style image size from ini file 
foreach($classes as $class){ 
foreach($cn as $k=>$v){ 
if($k==$class){ 
if($v['width'] && $v['height']){ 
$thumbWidth = $v['width']; 
$thumbHeight = $v['height']; 
}elseif($v['width']){ 
$thumbWidth = $v['width']; 
$thumbHeight = round($thumbWidth/$x); 
}elseif($v['height']){ 
$thumbHeight = $v['height']; 
$thumbWidth = round($thumbHeight*$x); 
}else{ 
$thumbWidth = $size[0]; 
$thumbHeight = $size[1]; 
} 
break; 
} 
} 
if(!isset($thumbHeight) && !isset($thumbWidth)) die('Ini file Settings error!'); 

$nimg = $name[0].'_'.$class.'.'.$suffix;//New image file name 
$source = imagecreatefromjpeg($oimg); 
$thumb = imagecreatetruecolor($thumbWidth, $thumbHeight); 
imagecopyresampled($thumb,$source,0,0,0,0,$thumbWidth,$thumbHeight,$size[0],$size[1]); 

if($suffix=='jpg') $method = 'imagejpeg'; 
else $method='image'.$suffix; 
$method($thumb, $nimg); 
imagedestroy($thumb);//Release the image source 
imagedestroy($source); 
} 
?>