Why the difference in images?
The image of W. Graham Robertson
is taken from the Tate Gallery website. Sargent's painting is very dark
(darker than the image that I got from the Art Renewal Center which is
at my first
page for Graham Robertson). The Tate's is probably a truer representation
of the painting -- though you can see very little given its size.
I like the ARC image, however, because
it shows more of the detail and is physically larger -- oh well -- Such
is life when you're dealing with images and not the real thing.