I have set Viewport settings on my site for mobile devices so hope this will improve page scaling and rendering for mobile devices.
Note though that images are rendered to fit on the screens, so if you are viewing in portrait mode and the photo is a landscape photo, it may appear a bit skewed or squashed to fit. What I find works well for this (as a workaround unless I can find a better solution) is to rotate the mobile device to landscape mode which renders the photo fine. I will anyway try and use a squarer format for photos in future which should render much better.