Ancient books weren't usually written with our photographic expectations in mind. By that I mean that since the advent of the scientific age, we expect documents from the time to be almost as written descriptions of what happened exactly as a neutral camera-man were filming it all.
Most writers though, specially religious ones, would work more with symbolism and poetry than we are used to expect. And part of literacy was related to be able to understand this symbolic meanings and see the facts they referred to.
When the facts being described were miraculous themselves, and were described with intense symbolic poetry, the text becomes almost completely opaque to the average modern reader.
Using the dragon example from the other thread, "fighting dragons" could mean fighting an actual snake, fighting a political power that was seen so evil as to be an icon of the devil or the ascetic fight with demons themselves. Saint George icon simply puts the saint in the apocalyptic vision where the dragon persecutes the woman (seen at the background of the icon), to show both his spiritual struggle, his defense of the Church against the spiritual evil manifest in the political powers of the age, and to teach us that whenever we fight evil we are somehow taking part in the war of the Apocalypse.
