Image moderators and game moderators.

[Jupiter]

Image moderators
They will moderate skin uploads. This would prevent inappropriate skins. From what I know there hasn't been a major problem with that...yet.
It's better to have it ready before something bad happens.

So basically this is how it works.
User uploads skin to Skins page or through the change skins page. (If uploaded through change skin page it will display as a question mark and as the default skin ingame until it's approved).
After the user uploads a skin it's sent to the moderation panel where they see the template of the skin and the user who uploaded it. They can either Accept it or Decline it.
If the skin is declined it is immediately deleted from the skins page (No point in just leaving it there if it's useless).

Game moderators
These moderators will focus all their time moderating on games. If a game is reported for breaking the rules they will have to play the game. (Looking at the thumbnail won't always display the rule breaking content).
If the moderators decide that the game breaks the rules they can close down the game. This won't delete the game file but it will turn the thumbnail into a giant X and make the game unplayable. (It won't remove the actual game file in case a moderator makes a mistake) If this happens by mistake a user can simply contact a moderator and get the game restored back.

Those are my ideas.