Frank Frazetta was an enormously popular American fantasy and science fiction artist who had a huge influence on the generations of artists who succeeded him (including the lead artist for the Legend of Zelda series, and the creator of He-man). He is best known for his work in sword-and-sorcery fantasy stories, providing iconic imagery for Conan as well as Edgar Rice Burrough's Tarzan and Barsoom series.
Perhaps my favorite depiction of Conan the Barbarian. This appears on the cover of Volume 1 of the Ace Paperback Conan series. I like to think of this painting as an allegory suggesting the internal fight that wages within each human's soul between the "animalistic" impulses and controlling agency of the mind. And so, according to this logic, Conan the Barbarian is actually the avatar of reason, and self-discipline, and morality, and all of that stuff.