On my Mavic Pro, photos were always 4000X3000, 12 MP. Now, they seem to be only 9 MP. What changed?
         Mike Freeman

Did you change the aspect ratio?

I would suggest as above, you have changed from 4:3 to 16:9 aspect ratio which would result in a lower MP image.
Check your settings in photos.

Thank you for reaching out. all the previous reply is correct you just need to choose the different Aspect ratio.

Thanks! I don’t know how it got changed, but that was it.

That sounds like the Mavic 2 zoom at 4000x3000 (12MP). The pro should be at 20MP. I am having an issue here now and was about to make a post about my resolution moving from 12MP to 960x720px... No idea why and the options to change resolution are nowhere to be found now.