To take this last point first, the Alexandrian authors of the [Greek text omitted] seem to have invented most of the images they were rhetoricalizing;(17) the shield of Achilles has a quantity of matter represented on it unlike any shield that existed in Homeric times or could ever exist; and even Alberti, whom we might appeal to as an example of the professional artist writing theory, devotes much of his descriptive power in De Pictura to visual objects he has never seen and only knows about from other people's verbal accounts.
Horace in the Ars Poetica is, of course, the author of the famous "ut pictura poesis" (lines 361-65); equally significant is the opening of the epistle where Horace attacks poetic indecorousness by comparing it to a painting of a grotesque misshapen body.
23 He is following Horace's "ut pictura poesis" and, more proximately, the repeated use of the analogy in Scaliger, e.
Herbert and the Visual Arts: Ut Pictura Poesis: An Opening in 'The Windows.
Ut Pictura Poesis: A Selective, Annotated Bibliography of Books and Articles, Published Between 1900 and 1980, on the Interrelation of Literature and Painting from 1400 to 1800.