Or just have full width ‘layers’ with an inner div set to the required width.
Right. Just what Paulie said or put your full-width photo outside the wrapper in the markup. Nothing wrong with that. You can structure it in a variety of ways that all work.
What I generally do is have a wrapper that is a class and makes no assumptions about what’s in it. Therefore… I can wrap what I want and NOT WRAP what I don’t. That’s just one approach and I don’t always use it but it works well most of the time.