缺点：长宽不一的图片会被拉伸变形，不能智能裁切，需要智能裁切的，请自行研究。
<?php
$config = array();
$config['path'] = "./";
$config['t_width'] = 120;
$config['t_height'] = 98;
$config['ignore'] = array("",".","..");
$config['prefix'] = "thumb_";
$done = 0;
define("IMAGE_JPG", 2);
define("ENDL", "n");
if($handle = opendir($config['path'])) {
while(false !== ($file = readdir($handle))) {
if(!array_search($file,$config['ignore'])) {

list($im_width, $im_height, $type) = getimagesize($file);
if($type != IMAGE_JPG) {
continue;
}

$op .= "found -> <a href='http://www.gimoo.net/t/1409/{$file}'>$file</a>" . ENDL;
$im = @imagecreatefromjpeg($file);
if(!$im) {
$op .= "fail -> couldn't create sour image pointer." . ENDL;
continue;
}

if(file_exists($config['prefix'] . $file) || substr($file, 0, strlen($config['prefix'])) == $config['prefix']) {
$op .= "note -> this file has already got a thumbnail." . ENDL;
continue;
}
$to = imagecreatetruecolor($config['t_width'],$config['t_height']);
if(!$to) {
$op .= "fail -> couldn't create dest image pointer." . ENDL;
continue;
}

if(!imagecopyresampled($to, $im, 0, 0, 0, 0, $config['t_width'], $config['t_height'], $im_width, $im_height)) {
$op .= "fail -> couldn't create thumbnail. php fail." . ENDL;
continue;
}

//保存文件
imagejpeg($to, $config['prefix'] . $file);
$op .= "done -> created thumb: <a href='http://www.gimoo.net/t/1409/{$config['prefix']}{$file}'>{$config['prefix']}{$file}</a>" . ENDL;
$done++;
}
}
}
closedir($handle);
$op .= "fin -> {$done} file(s) written" . ENDL;
echo "<pre>";
echo $op;
echo "</pre>";
exit;
?>

PHP教程