How to set up a rule so end users can submit a photo on a gallery page but it needs admin approval to actually be live?

The title says it all. How would I set up a rule so end users can submit a photo on a gallery page but it needs admin approval to actually be live on the website? I understand I can set up people permissions so that they can create new content within a certain photo gallery content type, I've got that part down but how would I tie a rule in to do what I want? Or am I going about this all wrong?