That should list all the newest screenshot saturday shots. It only pulls static images though and not animated ones. That page is more of a latest #screenshotsaturday dump though. The all time top is still not working correctly but the weekly and monthly are.
Rankings are based off of votes in the "game".. but also the game does have a lifetime limit for the number of points you can gain playing it. It was set pretty high but some people managed to actually hit the cap (including me).