Thank you for your opinions! It's always helpful knowing other views.
As I mentioned, initially I wanted to do the screenshots just for myself, but then decided to put some on the Wiki, according to Steo's motto: Better than nothing / better than just in-game screenshots.
The lighting could make many/all objects appear nicer. However, many objects can be seen in different levels, meaning they look (very) different depending on the level and even on the location within the level. Choosing a random location would leave me quite unsatisfied as I'd know that, with the possibilities/options I allowed myself, I could have achieved a (way) better result; and carefully evaluating the different locations would simply cost way too much time. Another problem with the lighting (the way I see it) is that e.g. the different Teensies (Griskin, Tufkin, Otto, ...) probably would appear quite different from each other, even though they actually aren't. Without the lighting, however, they look the way they sort of actually are and not just the way they appear in game, which is what I was aiming for, even though they might look less familiar then.
The angles at which I pointed the camera at the objects could have been chosen better as well, but, again, I tend to spend too much time optimizing things when I don't give myself some restrictions; in this case I simply restricted myself to some common angles/views (front, isometric, side). Out of this three I always chose the one where most details are visible.
So, yes, with lighting and different perspectives, better looking results could/would have been achieved, but there were reasons why I didn't decide for this approach (mainly lack of reproducibility, arbitrariness and, ironically, dissatisfaction; probably also lack of artistic taste

).
So, don't hold back replacing/removing the pictures!
