As indicated by the caption, this image shows the Mackay mansion's Gothic room circa 1926.
The caption accompanying this photograph reads as follows:
Circa 1926: The Gothic room
The door entry into the Gothic room from the entrance hall can be seen here.
An image of a painting by Sir John Lavery ( 1856-1941) titled "Tea Time in the Gothic Room at Harbor Hill dating to 1927 and showing Clarence Mackay, his son John William Mackay, and his mother, Louise, Mrs. John William Mackay taking tea has been placed here in the Library.
See Harbor Hill, Clarence Hungerford Mackay's Mansion.