What is the value of a blue boy painting?

Gainsborough's "Blue Boy" is in the Huntington Library, and isn't for sale. It sold in 1921 for the highest price ever, up to that point, the equivalent of about $7.75 million in 2010 dollars; however, top rate fine art appreciates faster than inflation, and it probably is worth than the Cezanne of "Card Players" that sold in a 2011 auction for $250 million.

They say Social Security will soon be broke; it's time to lay in a stock of oil paints and black velvet, and learn to paint Elvis, or dogs playing Poker.