Mary Hamilton Humes was the wife of Samuel Humes and sister of Elizabeth Hamilton, the wife of James Humes, and thus the aunt of Mary Humes.
Jacob Eicholtz is a famous portrait painter from early 1800’s Philadelphia. He grew up in the Lancaster PA area. His paintings can be found in museums including the Smithsonian Portrait Gallery and the Metropolitan Museum of Art. This painting of Mary Hamilton Humes complements the one of her husband Samuel Humes which can be found at the Met.
From the perspective of family history, this is an example of two brothers marrying two sisters in colonial America, so that the children (like Mary Humes) are double cousins. From a DNA perspective this causes a cascade of distant cousins all pointing back to the original Humes and Hamiltons from Northern Ireland.