Not sure if you’d consider this a bug or a feature request… ~=On mobile, to go to the next photo by swiping the screen, I need to swipe from the very edge of the screen. This is tricky on my Samsung Galaxy S10 as the screen is curved along the edges and I have a case on the phone.
PhotoStructure should go to the next photo when I swipe left on any part of the photo (not just from the very edge), and similarly it should go to the previous photo when I swipe right on any part of the photo.
Swipe navigation actually isn’t implemented yet, but several others have asked for this. I wonder if you’re actually performing a swipe-to-go-back gesture?
Interestingly, tap-to-navigate on mobile is now is almost as prevalent as swipe-to-navigate, but ideally both would be supported.
I’ll make this a feature request. 
Haha, you’re completely right! My mistake. I didn’t realise Android Chrome did that as I’ve never tried swiping on a webpage before.
This would be great to have on larger tablets, as it would allow navigating in both directions with either hand. The ability to swipe up and down could be useful for other types of navigation as well. The behaviour and speed of the gesture would ideally be customized to feel native to the current platform.