Cached Leopard Mail images: friend or foe?

TUAW reader Simon wrote in to us, to share one of his favorite new Leopard features--and its unexpected consequences. After clicking on an All Images search, he was astonished to find any number of odd gifs and jpgs pertaining to, um, Viagra, and er, male enhancement. He quickly realized that All Images was displaying bits (and we do mean bits) from Mail's download cache. This means that although he set Mail to not download HTML images, they're getting downloaded anyway. Simple annoyance or possible security breech? You tell us in the comments.