Harmy said:
These are apparently high def scans of the original version and for some reason they are cropped to 4:3. They could be some promo materials of course but still.
Those ARE promo stills. Take a look here:
http://www.moviepicturedb.com/movie/0076759/Star-Wars.html
You need to purchase download credits though to download the files at high resolution. For color reference the small previews should be good enough though.