pixelfed-imgproxy-apache2/imgproxy/index.php

<?php

$url = trim($_GET['url']);

# check url matches a https://domain/storage/whatever.jpeg url for images
if (preg_match('/^https:\/\/[^\/]+\/storage\/[^\s\%]+\.(png|jpg|jpeg)(\?v=[^\&])?$/', $url) ||
	preg_match('/^https:\/\/[^\/]+\/system\/media_attachments\/[^\s\%]+\.(png|jpg|jpeg)(\?v=[^\&])?$/', $url)) {
	if (preg_match('/^.*\.png(\?v=[^\&])?$/', $url))
		header('Content-Type: image/png');
	else if (preg_match('/^.*\.(jpg|jpeg)(\?v=[^\&])?$/', $url))
		header('Content-Type: image/jpeg');
	echo file_get_contents($url);
}

?>