Pitt’s picture, n. — Green’s Dictionary of Slang

Pitt’s picture n.

[in order to help finance the war against the American colonists, Prime Minister William Pitt (1759–1806) increased the tax on windows, charging householders for each one they owned. This was generally disliked and the poor and mean preferred to brick up windows rather than pay the tax]

a bricked-up window.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Pitt’s Picture. A Window stopt up on the inside, to save the Tax imposed in that Gentleman’s Administration.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn).
1811		Lex. Balatronicum.
1822		Life and Trial of James Mackcoull 32: The place alloted by our hero for the most valuable stolen property he received, was a recess formed by the shutting up of a window, termed by him Pitt’s picture.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.