Customer and picture ratings

I have a quick question. I like that customer can pic their favorites by creating event.
Now - customer picked their favorites and they want me let you know what pictures they like better than others.

Is there any way for customer to apply and change star rating without posting new comment? Also filter by rating would be useful.

I can see customer to change their mind about some pictures and it makes no sense to me post new comment just to to give a picture rating.

May be I am missing something.

I guess my question is..

1. How customer select more or less preferable pictures within their favorites?

2. If there is a way to filter/select lets say top favorite 5 star pictures within favorites in event?

I hope it makes sense. Thanks Charles