Such amazing art in that slideshow. Its amazing how tightly the live action scenes of the movie matched those pics. Were all of these drawn prior to the movie?
If I remember correctly, most of the paintings for the other movies were done mainly as marketing and promotional items, for books, posters, and art sets. I don't think he was as involved with the rest of the original trilogy as with the first. By then Lucas had a whole army of artists working for him.
The original trilogy owes most of its look and feel to McQuarrie.
I always liked the original set of paintings, where things looked different and strange. I actually saw many of them before the movie came out, as they were used to promote the film in science fiction fan magazines. (The first movie came out between my junior and senior years of high school.) The later paintings are much more "on model" than the original, exploratory paintings, and not as fanciful.
My cousin was a film critic at the time, and somewhere my brother has a press kit that my cousin gave to him that included a lot of goodies, including a very nice, oversized black portfolio of the original set of paintings. I wouldn't be surprised to find it's worth something these days, but my brother and I spent hours pouring over those paintings, and enjoying every detail.
It's one of things that got us involved in the special effects industry years later. So I feel I own Mr. McQuarrie quite a bit.
He was later to generalize this into a more general set of archetypes, but it seems to me that the first movie was very naive, in the literary sense, and very much a reflection of his love of the fantasy narratives of his youth.