You take a lot of photos.
Try and retry.
You get one with the best "moment".
It is always a skill to know "when" it is the "moment" to take the photo. One which you get by trying over and over again, then you "feel" when it is right.
That's about it.
They can't control your portfolio outside of work.
As for those done at work - depending on your contract it's made within work and work property. That's about it.