For how contemporaries viewed images ('the period eye'), see
Michael Baxandall, Painting and Experience in Fifteenth-century Italy, 2nd ed. (Oxford, 1988), Chapter 2
Stuart Clark, Vanities of the Eye. Vision in Early Modern European Culture (Oxford, 2007)
Bob Scribner, 'Ways of seeing in the age of Dürer', in Dagmar Eichberger and Charles Zika (eds), Dürer and his Culture (Cambridge, 1998), pp. 93-117.
Michael L. Wilson, 'Visual Culture: A Useful Category of Historical Analysis?' in The Nineteenth-Century Visual Culture Reader, ed. Vanessa R. Schwartz and Jeannene M. Przyblyski (New York, 2004), pp. 26-33.