Focus on the dogs, cats, and pet birds

An excerpt from poet Alfred Corn’s Notes on Ekphrasis, a solid overview of the practice:

Actually, a poem about an obscure painting is also at a disadvantage. Where the original image is well known, we can compare it to the poet's version of what it contains; and the poet's departures from the original, or inaccurate interpretations of it, are sometimes revealing. Without the original image, though, we are forced to trust the poet's description as being accurate, and we are unable to know where it is not. Meanwhile, the compositional task is much more difficult in such cases since the text of the poem has to convey all the relevant visual information, while still qualifying as poetry. On the other hand, if the subject is, say, Leonardo's Mona Lisa, or any other very famous work of art, there's no need to give a detailed description; the audience already knows what's in the painting.

A disadvantage, though, of using very great works of visual art as a subject for ekphrasis is that the comparison between the original and the poem about it may prove too unfavorable. Readers may wonder why they should bother reading a moderately effective poem when they could instead look at the great painting it was based on. If the poem doesn't contain something more than was already available to the audience, it will strike the reader as superfluous, the secondary product of someone too dependent on the earlier, greater work.

The reader may also wonder why the description wasn't done in prose rather than in lines of poetry. All art historians and critics agree that complete and accurate verbal descriptions of visual art are very hard to achieve, even in prose. When the expectations associated with good poetry are part of the goal as well, we see that writing a good ekphrastic poem is a formidable task indeed. The aim of drafting a text entirely adequate to its source, giving a verbal equivalent to every detail in the subject work, is probably too lofty. A more realistic goal is to give a partial account of the work.
Once the ambition of producing a complete and accurate description is put aside, a poem can provide new aspects for a work of visual art. It can provide a special angle of approach not usually brought to bear on the original. For example, in a banqueting scene, the poem might, instead of describing the revelers, focus on the dogs, cats, and pet birds given free rein in the scene.