I have a print of Blue Boy in the old frame it has been in our family for about 70 yrs. can you tel

I have a print of Blue Boy in the old frame it has been in our family for about 70 yrs. can you tel

Question about The Blue Boy (Gainsborough)

I have a boy blue picture on the back it says Sir Thomas Gains borough British 1727-1788 oil on canvas 70x48 inches Henry E Huntington Library and Art Gallery San Marino California