I think I was reading a book about digital illustration when it started talking a bit about the influences of one of the fantasy artists in it and he mentioned Frazetta, showing one of his pieces of the Death Dealer on his horse, which I thought was amazing.
Frank Frazetta (1928-2010) was an American illustrator who began working in the comic industry where he struggled in the beginning to find a decent income until he managed to capture the attention of the United Artists studios who gave him work painting for movie posters. His style went high in demand afterwards and he was sought after by many famous personalities to do the covers for their albums, posters, etc.
I remember once I read one of his instructors told him, after seeing one of his early works, that he had to work more on his anatomy skills. He grabbed some books on the subject and after a night’s work, the next morning he said “now I know anatomy” showing a considerable improvement.
Here’s one website where you can check a lot of his work and also read some more about him: http://frankfrazetta.net/index.html