File to minify all png files in a dir

tinypng.php

<?php

/*
 * Usage: php tinypng.php /absolute/path/
 * OR
 * Usage: php tinypng.php relative/path/
 * 
 * Requirement: "tmp" dir in the same path of tinypng.php
 */

$web = curl_init();
curl_setopt($web, CURLOPT_HEADER, 0);
curl_setopt($web, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($web, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($web, CURLOPT_RETURNTRANSFER, true);
curl_setopt($web, CURLOPT_USERAGENT, "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:16.0) Gecko/20100101 Firefox/16.0");
curl_setopt($web, CURLOPT_URL, 'http://tinypng.org/api/shrink');
curl_setopt($web, CURLOPT_POST, 1);

$dir = realpath($argv[1]);

if ($handle = opendir($dir)) {
	while (false !== ($entry = readdir($handle))) {
		$filename = $dir.'/'.$entry;
		if(mime_content_type($filename) == 'image/png') {
			echo $filename."\n";
			curl_setopt($web, CURLOPT_POSTFIELDS, file_get_contents($filename));
			$result = json_decode(curl_exec($web));
			file_put_contents(realpath('tmp').'/'.$entry, file_get_contents($result->output->url));
		}
	}
	closedir($handle);
}