It is important for models and actors to have good photographs for their portfolio. Not just a good picture, since all phones have quite good cameras now a days. Agencies require professional portfolio photos where the uniqueness of the person is highlighted.
Due to my vast experience in photography, I know what kind of portraits are useful to have in a portfolio. Because of this agencies refer their models to me to either start their portfolio or to expand it. Where needed, I coach the model to get the best outcome.