On Firefox for Android, the individual photo pages all seem to stretch the image horizontally to the screen width, wrecking the aspect ratio.
Maybe that's not a browser/OS combo that matters, but figured it was worth mentioning.
There are no "individual photo pages", those are direct links to JPEGs.
I just tried it in an Android emulator with the stock browser and it looks fine. In 60 seconds I could not figure out how to navigate the dependency hell necessary to install Firefox, so that's the end of my due diligence there.