It's funny actually. When standing on a planet, as most of us have done our whole lives, the "horizon" being horizontal just feels right. But the second any one of us plays a space video game, it pretty much immediately feels right to travel "beside" planets, instead of over or under them. Even though functionally the only difference is how you orient your craft relative to the planet of course. And, in most space games I've played, you even have more rotational thrusters for pitch than you do for yaw, so you'd think over or under would still feel better as you have more control.

But keeping the planet to your side is still the most common behaviour, and completely unprompted. So while these photos were of course rotated, they don't at all look weird to me, and I only thought about why when they looked weird to you. Hehe. I have approached thousands of planets this same way.