I wonder what the process of creating art would be like in the wizarding world, where paintings are

I wonder what the process of creating art would be like in the wizarding world, where paintings are alive and sentient. At what point does that happen? When you decide a painting is complete? Or do they move around during the sketch stage and you have to beg them to stay still long enough to draw in the details? If you doodle a stick figure on a scrap of paper and throw it away, what happens? It’d be neat if there was a magical art class offered at Hogwarts that explained stuff like this. (I guess all of Hogwarts’ extracurricular funding must go towards Quiddich though.)