Oh but I created all these artworks myself your honor
If I recall there was some case in which the authorship of some picture was contested, and the judge asked the people involved to draw something right there, in court.
So the same thing would happen. They'd ask you "okay, so how did you draw it? What tools do your use? Can you show us sketches? Can you draw something here, right now?"
My "paint" is software, m'Lud. Some of it is pre-made "paint" that someone else wrote, like tubes of paint from an art-shop; some of it is my own modifications, analogous to grinding your own pigments.