Graphic
There are two portraits of Dr Robert Thoroton at Flintham Hall, near Newark:
Portraits of Dr Robert Thoroton at Flintham Hall. Images courtesy of Sir Robert Hildyard.Nottingham City Council Museums and Art Galleries hold an oil painting entitled 'Portrait of a Man (thought to be Dr Robert Thoroton, 1623–1678)' (artuk.org/discover/artworks/portrait-of-a-man-47088). However, the portrait is very unlikely to be of Robert Thoroton himself and is possibly of a later member of the family.
See the following articles for further discussion of the portraits:
Blagg, T. M., 'A Note on the Reputed Portrait of Robert Thoroton at Nottingham Castle', Transactions of the Thoroton Society, 44, 1940, 68-71.
Pitman, C. F., 'A Consideration of Two Reputed Portraits of Robert Thoroton, M.D. 1623-4 [?]-1678', Transactions of the Thoroton Society, 43, 1939, 66-71.