A person with a purple shirt is painting an image of a woman on a white wall.
A woman paints a portrait of a person.
A person with a purple shirt could be either a man or a woman. We can't assume the gender of the painter.
person with a purple shirt  painting an image of a woman on a white wall doesn't mean that person is a woman.
A person doesn't have to be a woman. An Image of a woman doesn't have to be a portrait.