I've had photographs taken for portraits because I very much prefer working from the photographs than from models... I couldn't attempt to do a portrait from photographs of somebody I didn't know.
Some artists leave remarkable things which, a 100 years later, don't work at all. I have left my mark; my work is hung in museums, but maybe one day the Tate Gallery or the other museums will banish me to the cellar... you never know.
Lastly, I would address one general admonition to all: that they consider what are the true ends of knowledge, and that they seek it not either for pleasure of the mind, or for contention, or for superiority to others, or for profit, or fame, or power, or any of these inferior things: but for the benefit and use of life; and that they perfect and govern it in charity.
Men ought to find the difference between saltiness and bitterness. Certainly, he that hath a satirical vein, as he maketh others afraid of his wit, so he had need be afraid of others' memory.