I found such photomontages some months ago without using software. Here another example:


Also, I did a research to find out who first published these compositions. The
Hemeroteca Municipal de Lisboa (a library not for books but for journals) has a special page with roughly 20 publications of the 1967 visit of Paul VI in Fátima:
hemerotecadigital.cm-lisboa.pt/EFEMERIDES/fatima/fatima.htmThe journal Stella ("revista católica de cultura feminina") is a publication of the
Congregação das Irmãs Reparadoras de Nossa Senhora de Fátima. The issues of May 1967 and June 1967 can be found
here.
The titlepage of May 1967 shows the following photomontage:

This issue contains a total of three such photomontages (see link above) including the one Chonowski shows.
Then there is the monthly periodical
Fátima 50 ("revista mensal de actualidades docuмental e ilustrada") published by the "Santuário de Nossa Senhora de Fátima", which a few weeks after the event republished two of the same photomontages.