Those are indeed illustrations of archers.
Did any archers actually fight in that sort of armor? If so, how many? They might have.
Knowing how artists work then and now, I wouldn't put much stock in period illustrations unless confirmed by hard evidence such as financial records of equipment purchases. You really need multiple sources to draw any conclusions.
Look at our own way of portraying medieval warfare. With all of our knowledge and science we still portray medieval battles as a large barroom brawl of individuals (see Braveheart).
And there's the way that we portray 20th century warfare. Compare the typical movie firefight with the countless YouTube videos of fights in Iraq, Afghanistan, Syria, and Ukraine. They have nothing to do with one another.
Art is just art and must be taken with a shaker of salt. Artists and their patrons want visually impressive and exciting representations of reality, often with an agenda ("Look how impressive MY archers look!"). And they necessarily both exaggerate and simplify their subjects for clarity and impact. Reality tends to be more complicated and messy.
takes a look at flexible roads made from long-lasting flexible resin.