Got a base script of the internet and modified it to retain image preportions. Tell me if it works!
<?
$image="new.jpg";
$old_w = imagesx($image);
$old_h = imagesy($image);
$new_w = 100;
$new_h = $new_w * $$old_h / $old_w;
header("Content-type: image/jpeg");
$dst_img=ImageCreate($new_w,$new_h);
$src_img=ImageCreateFromJpeg($image);
ImageCopyResized($dst_img,$src_img,0,0,0,0,$new_w,$new_h,ImageSX($src_img),ImageSY($src_img));
ImageJpeg($dst_img);
ImageDestroy($dst_img);
ImageDestroy($src_img);
?>
