Possible Clues:

• Gallery overlooking the Thames
• ''Little Man ___'' (Jodie Foster movie)
• Site of some Sargents
• Where many Sargents hang, with 'the'
• 'Ode to the Confederate Dead' poet
• Museum named for a sugar magnate
• Some art at expensive gallery
• Renowned London gallery
• 'King Lear' bowdlerizer
• Home to many John Constable works, with 'the'