PHP按比例生成縮略圖片

set_time_limit(0);
$handle = opendir('icon/.');
while( false !== ($file = readdir($handle)) ){
if($file != '.' && $file != '..'){
$im  = imagecreatefromjpeg('./icon/'.$file);
$pic = imagecreatetruecolor(64,64);
imagecopyresampled($pic,$im,0,0,0,0,64,64,160,160);
imagejpeg($pic,'./icon64/'.$file,100);
}

}
echo 'Well Done^-^!';