This is John Gloucester ((1776-1822). We have not yet found a picture of William Thomas Catto. The main picture is the First African Presbyterian Church in Philadelphia, PA, c. 1890.
A brief biography of John Gloucester on the Presbyterians of the Past website can be found here.
A Semi-Centenary Discourse - A History of the the First African Presbyterian Church, Philadelphia, and a Brief Notice of Rev. John Gloucester