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.htm


The 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.

I suspect that the true sister Lúcia was "on stage" together with Paul VI., and can be seen in the RTP video of the event. But then, the false sister Lúcia is inserted into some photos already in 1967.


Paulo VI – Peregrino de Fátima, Video on rtp.pt, 45'00"


RTP = Rádio e Televisão de Portugal

Lol, would that be the “real” Paul VI, or the doppelgänger with the misplaced earlobes?

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Not to change the topic, but I couldn't help but notice this one comment under the OP article on the source page:
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August 15, 2018 at 6:17 AM
Our Lady would never say "the survivors woujld [would] envy the dead". That is a false apparition from the Novus Ordo and in front of the Novus Ordo empty tabernacle during a Novus Ordo "Eucharistic prayer" from Vatican II Bishop. Like many false apparitions and Novus Ordo carry'ons it is promoted by Bishop Williamson to good folk, perhaps good folk like you. Don't fall for it. It might sound real but the Novus Ordo Church is not the Catholic Church and if they approve an apparition is [it] holds no more water than their approval of the New Mass and various heresies. Stay with Fatima, La Salette, Rue de Bac and all pre-Vatican II approved apparitions and stay away from Bishop Williamson the deceiver and ?Rosicrucian poetry-teller.
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Somebody has some pretty powerful animosity toward +RW. Almost as if they're ready to blame him for all these problems -- who knows what he's going to be accused of next! Perhaps it's a crypto-Zionist creeping in to do damage by subterfuge, getting even for the unforgivable sin of "anti-Semitism!"

St. Therese is also usually depicted as holding a crucifix with roses on/around it.  Maybe she was a Rosicrucian too?

Above 'Lucy's' head I see the mysterious Babuska Lady ... In the photo of the Pope alone, she is by his nose.

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Good eye! In the second photo her face is overexposed and looking whiter, like the rest of the photo. She appears to have moved a bit upwards, and to the right around 5 feet, using the TV camera's position as a benchmark. In the second photo you can only see the top left corner of the TV camera, since the fake Lucy was overdubbed to cover most of the TV camera's frontal aspect.
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If you look carefully you can see several identical faces in the crowd in the two photos.
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All considered, either Paul VI was moving forward, either walking or on a moving platform, or else the camera was moving to the left, or perhaps BOTH, because the position of the TV camera to his left and the columns of the building behind it are things that would not have been moving, yet they are in two different positions.
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The image on top (without so-called Lucy) might have occurred first, then the camera would have moved to the right and upward a few feet, then the second photo would have been taken. The TV camera in the background having remained still, appears to have moved 6" to the right and 3" up compared to Paul VI. That means the camera taking these pictures would have moved to the right a foot or two (being a further distance away from Paul VI than the TV camera is behind him) and upwards about one foot. Notice how the angle of view in the second photo is slightly more looking downward than the first one was (first one is at eye level of Paul VI). This also explains why the crowd in the background appears to be higher in the second photo, because Paul VI is lower, and the camera has been angled downward to keep Paul VI in the center of the frame.
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There are several people to notice. A balding man with glasses to the right of the TV camera is clapping with his hands in two different phases of a clap in the first and second photo, plus, and because of this you might not recognize him, in the first photo his mouth is closed but in the second photo, it is open, so he would have been saying something out loud, pronouncing a "p" or "b" or "m" which require the closed lip position. The second photo is more overexposed than the first so this man appears to be in brighter light with whiter highlights on his nose, forehead, cheeks, chin and fingers. Notice too, to his left, another man looking downward is seen, the front of his face only, but in the second photo his nose is covered by the back of the head of the next man with dark hair.
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The dark-haired man in black jacket in the first photo turning to his left side directly behind Paul VI's left hand is also in the second photo, but all you can see is the back of his right shoulder, as his head is cropped off the photo on the right.
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In the event the source site deletes this set of photos, I've put them into the archives here for future reference.

All considered, either Paul VI was moving forward, either walking or on a moving platform, or else the camera was moving to the left, or perhaps BOTH

The image without Lucia was "shot" with  a TV camera by an RTP TV cameraman. The other image is a photography shot by a photographer from a slightly different angle.

The press often has a booth with a whole fleet of cameramen and cameras taking pictures at various papal events.

Above I posted a link to a page on the site of RTP TV with a 45 minute video of the event. Paul VI. arrives in a car at 18'50". It shows the whole situation with multiple TV cameras, photographers on the stage and in the crowd as well as a special scaffold with dozens of photographers.

So somebody found a way to insert the figure of a person (the fake Lucy) into the photo before the time of Photoshop, that is, at least before it went public.

Paul VI. visited Fátima on May 13, 1967. The photomontages appeared in the periodical "Stella" in the issue N.º 357, Maio de 1967.

There is a copy of the so-called Third Secret that seems to have been altered before the advent of Xerox or computers. It's on the TIA website. Atila Sinke-Guimaraes does an excellent job of unpacking the thing using subtle clues and his superior knowledge of Portuguese. (The letter is handwritten in that language.) But he makes no pretense of looking into the question of HOW the letter could have been faked.

Interesting. Could you please provide a link or pertinent keywords for a search on the TIA website?