While most people will understand if you ask them not to share photos until you've had a chance to pop something on social media yourself, an indefinite ban or a shopping list of what they can and can't use is one way to make sure they won't be dancing on the tables at the end of your reception. If you want to stay in control, keep your rules simple, and try to do it in a friendly way so your guests understand why you being the first person to share images with the rest of the world is so important to you.