<?php
        $max_size = 600; // KB
        $fp = opendir("./");

        while (($fn = readdir($fp)) !== FALSE) {
                if (filesize($fn) > 1024 * $max_size) {
                        echo "converting $fn ..\n";
                        `convert $fn -resize 60% $fn` ;
                }
        }
        closedir($fp);
?>