I really like eheath system thought you wouldn't be able to sort out any fake accounts, the only way would be to see with an ip address but then it could just be a friend/family that also has an account !!!
And as Bishop said it would be hard to convert all the old rating into the new system to keep every picture's rating legit.
But the system where you could see who rated your picture is an good idea, it would definitely reduce the down rating.
Than the question would be if it would be public or not, I personally think that if it is just for the owner of the picture it would be good, and have a tab "ratings" where you could see all the ratings on you pic and maybe have a report this rating (or something in the idea) !!!
The problem with this system that if the owner of the pic see's that someone didn't give a good rating (but not downrating like 1-3 on a good pic) he may just go and downrate the other users pic/vid..
An idea I had, would be that after 3-4-5 rating it there is a rating that is 5 points apart from the average rating of the 3-4-5 initial ratings, then a admin would be notified !!!
Example : if after 4 rating you have a average rating of 9.00 and the 5th rating is of 3 an admin would be notified.
I really like where this thread is going, can't wait to see what this is going to change !!!
And I almost laugh at today's top rated pictures page, everything under 8 !!!