Find where you modified it before.. without any modification Home points to the Piwigo installation diectory. Likely you have set $conf['gallery_url'] in your local config, remove it to keep the default
$conf['gallery_url'] = null;
of include/config_default.inc.php., or if that doesn't help then set the proper URL in your local config to
$conf['gallery_url'] = 'http://example.com/photo/';

And for example domains in posts use example.com instead of a porn site..