As the caption indicates, this image shows Stanford White's illustration of his intentions for the Mackay mansion's great hall.
The caption accompanying this image reads as follows:
Stanford White's compelling illustration of his intentions for Harbor Hill's great hall, amply justified his assurances to Clarence Mackay, that he would be getting a house which, with the exception of Hunt's Biltmore, was without peer
See Harbor Hill, Clarence Hungerford Mackay's Mansion.
