Possible meanings are 1) Jerusalem's leaders were beautiful to look at because they were physically healthy or 2) the leaders were morally pure as new snow and milk are pure white. (See: [[rc://en/ta/man/jit/figs-metaphor]])
"their bodies were redder than coral." This implies that they were healthy. Alternate translation: "their bodies were healthy and red" (See: [[rc://en/ta/man/jit/figs-explicit]])