It was the 70’s. It was Marvel comics. Marvel did have a Conan comic at the time. I think Roy Thomas and some others worked on the Conan book.

And it’s not like there’s an official movie poster anywhere that makes Luke into some buff dude with a sexy Leia at his knee. 😉

Weird depictions of Luke actually abound in early poster concepts. I think this one only appeared in the Art Of Star Wars book.

But unlike the Marvel icon, at least none of these show Luke standing around floating in a vacuum.