Upvote:11
The painting is quoted on the back cover of the book as "So Bright and Delicate", oil on canvas, by Aaron Robinson, 2009.
Source: the Amazon preview of the book. (https://www.amazon.co.uk/So-Bright-Delicate-Letters-Classics/dp/0141442476#reader_0141442476)
His website, for anyone interested: http://aaronrobinson.net/
His wordpress blog: https://earthtorobinson.wordpress.com/