William John Thomson RSA (3 October 1771 – 24 March 1845) was an American-born painter of silhouettes, portraits and miniatures who was active in Great Britain.

His younger brother, born in Edinburgh in 1778 was Anthony Todd Thomson, the doctor who had delivered Gaskell.

[6] He exhibited his work at The British Institution between 1809 - 1829 whilst living in London at 6 Charles Street, 41 Craven St and 111 The Strand.

His subjects face slightly to the right; their features are emphatically delineated, the left eye appearing overly large.

[9] Thomson was a miniaturist of very great eminence, although he sometimes exercised his talents on large portraits and small full-lengths.

To accuracy of execution he added great richness of effect, preciousness of finish, and depth of tone.

[11] On 17 April 1824, he was elected Associate Member of the Institution for the Encouragement of Fine Arts in Scotland which later became the Royal Scottish Academy.