So my girlfriend is writing her thesis on some art history stuff and she stumbled upon some piece of info which states that a certain guy that was publishing his art magazine at around 1922 , was often asking for cliches from other people in order to print stuff on it.

1. Does that mean he had to get a metal plate every time he wanted to post a picture of an artwork in his magazine?
2. Does that mean that the picture has always to be posted in the size that the metal plate has and that he can't change that and he just has to fit the size wherever possible in the magazine?

Then it was somewhere stated that after many times of use the quality of the picture was worse.
3) Does that mean that after using it consecutively the cliche "wore off" ?
4)Also how can the artworks be transferred to a cliche(aka a metal plate) and look accurate as they do? I mean they are detailed , with shadows and everything. How was that achieved? Did someone manage that with his own hands? How was it "put" into the metal plate? Look here for example http://anno.onb.ac.at/cgi-content/anno-plus?aid=maa&datum=1922&pos=1&size=45

Thank you.