I have one of the Australian releases of the trilogy (think it's the last release on VHS of the Original Trilogy), and this set of artwork is the set used. The artist's name is John Alvin, and I found some info on him when I went to find hi-res textless versions of these works online. Here is the page on John Alvin.
@Wer-Al_Zwowe:
Thank you man!! I have been searching for some hi-res versions of these for so long!! I still have 300dpi scans of my VHS covers sitting on my hard drive.