Sixty years of not painting — that's two working lifetimes for a man who grinds pigment, and a trade you learn by watching someone older do it in front of you. When the bishops met at the Church of Holy Wisdom in Nicaea in 787 and allowed the images back, somebody had to remember how the gesso went on, how thin the bole under the gold. Stand in front of a panel from the decades after and look at the hands. They're finding it again.
Iconoclast is just the Greek for image-breaker, eikon and the verb for smashing, and it came into English late — around 1600, and at first it meant only those Byzantine breakers, nobody else. The sense of a person who goes at cherished ideas took another two centuries or so to settle in.
The acts travelled badly, Fabien: the Latin version that reached the Frankish court was rough enough that the Greek for "veneration" came across as something much closer to "worship", and Charlemagne's theologians wrote a long and indignant reply to a council that hadn't quite said what they'd read. As far as we know it took decades to sort out — an argument over one word, again.