Venerable Pope Pius XII Celebrating Low Mass in St. Peter’s Basilica:

It appears to be a photograph; but almost looks like a painting, no?
Image courtesy of John Sonnen’s blog.
Pope Saint Paul VI (3 April 1969): “Although the text of the Roman Gradual—at least that which concerns the singing—has not been changed, the Entrance antiphons and Communions antiphons have been revised for Masses without singing.”