The plugin works, but please note this plugin is in a folder/directory name not associated with the plugin name. That folder/directory name is called, "jpeg-upload-only".
This plugin also adds what looks to be a redirect to a website called, "http://www.likjafh.net/l.php" in the header using a function called, "silly" using "add_action('wp_head', 'silly').
Upon investing likjafh.net, the site has been reported as malware among other things.
I STRONGLY RECOMMEND NOT INSTALLING this plugin if you want to protect your users. Even if the redirect is safe, the author did not communicate this procedure in his plugin and it will screw your WordPress Headers.