Small photo files from iPhone 7 Plus

I noticed that most of the photos are less than 2 MB. The largest I've seen is 2.2MB. I would expect full resolution 12 megapixel photos to be much larger. Looking at the photos from a friend's Samsung Galaxy S6 most of the full resolution photos are 4-6 MB and some are even over 6 MB. Is it possible I have some setting misconfigured that is resulting in photos that aren't shot at maximum resolution?

I was expecting stellar photos but actually so far I'm unimpressed compared to the S6 photos which is a much older and cheaper phone.

Thanks.