^ doubleKO has a quality collection of SW posters (much of which is high quality) - containing some John Berkey art:-
https://originaltrilogy.com/post/id/993765
&
and this auction site found by doubleKO often has some high quality SW images too:-
&
also SkyderHouseMafia also has a top collection of SW art (I think there is Berkey art in there too?), here:-
https://originaltrilogy.com/topic/Complete-Star-Wars-Poster-Collection/id/60955
Good luck with it - hope you find what you’re looking for.