Ever wondered about the identity of the artist behind most, if not all, of Martin Luther's image depictions?
Wonder no more. The man who rendered his artistic acumen to the cause of the Reformation was Lucas Cranach the Elder.
Wikipedia describes him as a "court painter to the Electors of Saxony for most of his career, and is known for his portraits, both of German princes and those of the leaders of the Protestant Reformation, whose cause he embraced with enthusiasm, becoming a close friend of Martin Luther."
More of his works here.