Photogravure and photomontage

While I was reading a guide of Indochina published by the Touring Club of France (this one is the 1910 version hold by the Library of Congress while the one I read is a longer version -published in 1911? - from the Bibliothèque nationale de France), I was struck by the photos used to illustrate the text in photomontage style. Some looks really uncanny, with a collage of a French woman on the photo of exotic site. Like this one,

There is mention of F. Bouché as the 'photograveur'. I then wrote to my colleague in the States who is specialist of artistic techniques in the 19th century, Rachel Skokowski.

She explained that 'photogravure' is a 19th-century photography technique that combines photography with etching (you basically transfer a photograph onto a metal plate that is then printed). The photograveur would be the person who made the prints, and is probably a different person from the one who took the original photos.

She also gives me useful links to read further: 

On photo gravure 
What is photogravure?
On photomontage and collage in the Encyclopedia of Nineteenth-Century Photography

I then discovered André Disdéri's 'carte mosaïque'. They are quite charming, and the Commune's one intrigues me. It is really upsetting to think about how many young people were killed during this event.