Bleating, neighing Curator of Fine Art at Ankh-Morpork's Royal Art Gallery. Sir Reynold is so posh, according to Fred Colon, that he is barely understandable. A tall, thin man, his speech is described as 'modulated yawning'.
His is a small part (with apologies to his dignity), but he is a vital character as he introduces one of the major plot components to Thud! - the missing Methodia Rascal painting The Battle of Koom Valley.
Comically gets put out - as the upper classes are wont to do when one of their inarguable words is actually argued with - when Sam Vimes asks him how art can be called 'interactive'.
There is a strong resemblance, in voice and manner and aesthetic, to Roundworld art critic Brian Sewell (London Evening Standard, the hernia-inducing Sunday heavy papers, and a frequently used pundit on those late night TV arts shows like "Newsnight Review" and "The South Bank Show"). Read his surname as "Sew-Well" in the (non)-seamstress Sandra Battye sense, and it can be seen how he mutates into "Reynold Stitched").
It is possibly germane to the character and personality that were he to exist on the Discworld, he would be a habitué of the Blue Cat Club: Sewell's autobiography lingers long and lovingly on cheerfully promiscuous gay experiences around the world, and all the young men who opened his eyes about the rarified world of Art Appreciation.
The panorama painting was invented in 1787 by Robert Barker, and the president of the Royal Society - who first disliked it, but later became an ardent supporter - was Sir Joshua Reynolds.