Some websites have a system where people publish mages first, then moderation has to review them, until a moderator sees the image, something really bad can happen and people will still see the image for a while.
Other websites have a system where people send the image to the website, but first, moderation has to see if there's nothing wrong with them, and then moderation has to approve that particular message to decide if it can be published or not.
How about something in between, if something is risque, NSFW or controversial, users can either publish directly, or they can ask for a moderation review, if there's something that goes against the rules but the user asked for a moderation, then there's no punishment for the user, unless the user is using the system to troll the moderation or something like that.