自个儿写的php生成缩略图

自己写的php生成缩略图
今天无聊，学了一下php生成 缩略图···然后发现书上说得太复杂了，于是自己搞了一个，不会被拉伸的东东····代码极其简介 ···所以不注释····

<?php        $sourceimage = '3.jpg';        $maxthumbWidth = 200;        $maxthumbHeight = 800;                $original = imagecreatefromjpeg($sourceimage);        $dims = getimagesize($sourceimage);                $a = $maxthumbWidth/$dims[0];        $b = $maxthumbHeight/$dims[1];        if($a<$b)        {                $thumbWidth = $maxthumbWidth;                $thumbHeight = $dims[1]*$a;        }        else         {                $thumbWidth = $dims[0]*$b;                $thumbHeight = $maxthumbHeight;        }                $thumb = imagecreatetruecolor($thumbWidth,$thumbHeight);                imagecopyresampled($thumb,$original,0,0,0,0,$thumbWidth,$thumbHeight,$dims[0],$dims[1]);                header("Content-type:image/jpeg");        imagejpeg($thumb);?>