$baseUrl

I had the similar task: to give access for uploading for each user separately.

In your case, I would change $baseUrl and $baseDir in config.php file based on the information where the user is located like that:

$url = explode("/",parse_url($_SERVER['PHP_SELF'], PHP_URL_PATH));
$baseUrl = "/" . $url[1] . "/images/";
$baseDir = "/home/public_html/" . $url[1] . "/images/";