According to the artist signature on antique postcards, the famous
Guardian Angel painting was originally created by H. Zabateri
(pseudonym of artist Hans Zatzka.) The Guardian Angel became very
famous when art prints were published in the USA under the artist
name of Lindberg. No one knows Lindberg's first name and it
seems to be the only painting for which he or she is known.
It's possible that Lindberg was more involved with creating
the lithograph templates. I doubt there was an actual painting by
Lindberg anywhere. Otto A Stemler did the same thing: he converted
many popular black and white engravings & illustrations from
the 1800's and turned them into beautiful full-color
lithograph art prints. Stemler's art prints of the life of
Jesus are still very popular today. So I suspect Lindberg's
story is the same. The inspired work of both Stemler and Lindberg
are still copied and recreated by modern artists.
Guardian Angel by Zabateri, aka Hans Zatzka