This is image is taken from an engraving (19 by 13.7 cm) by Cornelis Galle the Younger (1615--1678), a Flemish engraver. I suppose Harvard must be right, but Cornelis Galle the Elder (1576--1650) seems more likely to have made an engraving of the accession of the a pope in 1623. In fact, the image in Giorgio di Santillana's The Crime of Galileo (but not the online one at the Galileo Project site) shows the label Cor. Galle followed by what seems to be ``fe.'': the f-like letter may be the old-fashioned ``s'' in which case I'd take ``se.'' to be an abbreviation for senior. But would Cornelis Galle the Elder have marked himself as senior when his son was only a boy? As aforesaid Harvard must be right. The engraving is owned by Harvard's Fogg Museum with code number R6929 and the details can be found from Harvard University Art Museums collections on-line page.
The image is online at The Galileo Project's Urban VIII biography. The Galileo Project intimates that the image was digitized from Giorgio di Santillana's The Crime of Galileo (University of Chicago Press, 1955), p. 224ff. The Galileo Project gives the wrong page number (p. 172), unless they are using a different printing or edition from the hardcover original edition. The original image of Galle is certainly public domain, but I sure don't know if the reproduction in Santillana's book is public domain. Consequently, I decline to post the image myself.