Famous English portrait painters, British portrait painting, a list of websites
National Portrait Gallery, London, online picture library.
The Royal Society of Portrait Painters
Metropolitan Museum of Art collection of English portrait paintings, 1600–1800
British portrait painters, a list from Wikipedia.
Francis Bacon
Francis Bacon
Francis Bacon. The Tate Collection
Thomas Gainsborough
Sir Thomas Gainsborough. An image gallery.
Sir Thomas Gainsborough.
Art museums displaying works by Gainsborough.
Thomas Gainsborough. The National Gallery
Lady Anne Hamilton. Detroit Institute of Arts
Google Art Project: Thomas Gainsborough
Sir Henry Raeburn
Sir Henry Raeburn
Henry Raeburn, The National Portrait Gallery
Sir Henry Raeburn. The Tate Gallery
Sir Joshua Reynolds
Sir Joshua Reynolds
Sir Joshua Reynolds. The Royal Academy
Sir Joshua Reynolds. The Tate Gallery
George Romney
George Romney
George Romney The Courtauld Insitute
George Romney. The National Portrait Gallery
John Singer Sargent
John Singer Sargent Virtual Gallery
Elizabeth and Mary Linley by Thomas Gainsborough, Dulwich Picture Gallery