Michael,
The "paintings " on the official site are my original images. I have to assume that whoever created the site used this "painterly" effect to enhance the look of the site. The vividness in the photographs comes from a combination of the film I use(Velvia) and the use of a warming cross polarization filter which when photographed at a 90 degree angle to the sun will a create a deep saturation in the images. Given that every monitor is a different I not sure what degree of saturation you are seeing. As for the site itself, if you were to walk the course at the appropriate time of day and used polarized sunglasses you would witness colors somewhat the same as I have posted.
Jim
As Brad Klein had mentioned in his post, the "dunes/mounds" were created by the construction crew.