index.php does all the magic here, and loading that in the browser will generate the page each time, downloading any new cover images first.
If you want to set up a cronjob or something to update it every so often and then serve a static copy (which I recommend), you can essentially just do:
php index.php > index.html
Only issue is the paths are all local to the dir you stick this all in, so in your crontab you probably need to cd into that dir first.