The Christies (NY) auction catalog #Evans-8938, of 18 June 1998,pictures an excellent pair of portraits of a Mr. & Mrs. Brandt & Mary Schuyler, as item #260 in the auction (they sold for $25,300).
Mary was born 28 July 1722 & Brandt was born 17 July 1717.
I am scanning this page in case any of Mr. & Mrs. Schuyler's descendants might like a copy, either by email or by postal mail. Somebody in the family ought to have it--it's too good to be missed by the family.
My email address can be found by clicking on my name above.
If it were a portrait of a Mr. Pease, I'd certainly want someone to do the same for me.