Panini was also an architect, evidenced in his images and spacial reasoning. His masterful use of perspective and optics makes him stand apart, one of my all-time favorite Baroque painters. The painting was donated to the museum in 1968. The photos here I took on the occasion of my visit last spring.
The thrill of this image draws in the attention of the viewer who studies the wide vista and then small details of the scene. This style was typical of the artist -- he was one of the veduisti or "view painters" (his works illustrate highly detailed, large-scale images that compel the viewer to look closer).
The viewer's attention is drawn up to the images of the colorful banners of saints hanging from the rear ceiling of the nave. In those years we can assume this custom of suspended banners was a common sight at St. Peter's for the special occasions of canonizations. I don't know all the details. In any event, this custom died out many years ago. Perhaps one day it will be revived?
I include a full image of the painting below, mounted on the museum wall of almond-colored Roman damask. The Baroque frame is also fitting and does not take away from the image.