My Agnes, it’s called – the sketch of a tired young woman seated at a table, chin pressed against the back of her hand, eyelids drooping. It’s the sort of stolen image of a private moment that would today be captured on a mobile phone but in Dürer’s day – if you had the facility of Dürer – was immortalised in pen and ink.  This charming souvenir of the 23-year-old artist’s newly married wife is one of the chief delights of the Courtauld Gallery’s new exhib­ition “The Young Dürer: Drawing the Figure” (Somerset House, London, until 12 January 2014) – a moment of unselfconsciousness in the brilliantly precocious oeuvre of this most self-conscious of artists. Dürer rarely doodled to no purpose. The