In the art a Seraph (plural Seraphim) is most often represented as above, with six wings and covered with eyes. This iconography constitutes a compromise with the description of the Seraphim in Isaiah, "I saw also the Lord sitting upon a throne.… Above it stood the seraphim: each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly" (6:2). In the images the Seraphim will have a pair of wings to cover their feet and a pair to fly with, but they rarely cover their faces.
The eyes are not in Isaiah, rather they allude to the vision of the Heavenly Throne in Revelation: "Round about the throne were four living creatures, full of eyes before and behind" (4:6).
Even early images often ignore Isaiah and have the throne of the Lord attended by Archangels. Archangels have sceptres like Seraphim, but their form is basically human so they can be dressed out like imperial courtiers for a more stately look (example).
It is said that when St. Francis received the stigmata his first vision was of a seraph coming toward him. Then "he saw the image of a man crucified in the midst of the wings," as at right.
Prepared in 2015 by Richard Stracke, Emeritus Professor of English, Augusta University