I don't take a lot of photos on my Android mobile phone, but always hold the phone horizontally (landscape). I nearly always wait until the photos are uploaded to OneDrive (via wifi) and then look at the photos on a laptop or 32" monitor.

I sent some photos from my laptop to a relative who has Apple devices. They said ' Incidentally the photos of your bathroom are quite hard to see as they are very narrow top to bottom if that makes sense. Maybe it’s the way my phone has downloaded them.  Not seen on laptop.'

After reviewing my photos on my mobile phone and then on my laptop, those on the phone are dark and very narrow top to bottom. On my own laptop, they look good.

My understanding is a lot of people just use their mobile phone for everything. So, do people mainly hold they phone vertically (portrait) when taking a photo?