This is about using Photoshop to work with your image. Since there are a few thousand websites about Photoshop, there is no intention here to give any sort of tutorial. Almost anyone can put together a fairly convincing image of George Clooney standing next to Marilyn Monroe. We see sloppy photo editing exposed frequently, but it is not hard to create convincing images of just about anything. You don't even need to start with a camera — you can create images like we see in movies — that are entirely synthetic.
The degree to which you use Photoshop to alter your images is up to you. If you use Photoshop to achieve a practical goal, fine. If you use it to express something inner that you simply could not photograph, fine. If you use it to defraud people, not fine. If you use it to defraud people emotionally, well, I don't know. That's between you and your personal moral adviser.
Bottom Line: Photoshop and related programs allow images to be altered or synthesized without any boundaries.
But the reason Nicole has that scolding look on her face is to keep you honest in your use of Photoshop. Like Superman, you should use your powers for good, not evil.
170mm, f8, TTL flash