The Nantucket Historical Association has a few legal documents written and signed by Thomas Macy, but doesn't have a portrait. The only known artifact from Sarah's and Thomas' settlement on Nantucket (other than legal papers) is a rectangular wooden trencher bowl, about 14" x 9", with its original dark green paint on the outside.
Concerning John Macy, while there is no portrait of his generation either, there is one artifact... a very handsome slat-back chair with a rush seat that was in his household.
There are a few Macy portraits dating from the last decade of the 18th century. Two nice ones are in the Nantucket Historical Association... Obed Macy (the island historian) and his wife. There is also a nice portrait of Peleg Macy painted around 1790, which is in a private collection.
Your pride in Thomas Macy is justified, but don't forget the other half of the team, Sarah Hopcott Macy. She packed up her life in England and went with Grandfather Thomas to a wild land, then after building a life in Salisbury (and having 5 kids!), picked up and moved to Nantucket to start all over again. Plus she had to live all that time with a husband who made a habit of snubbing the very powerful religious leadership of Massachusetts Bay Colony!