slaughters: didn't mean to be gruff.
i just didn't see what a "liquid layout" has to do with the question.
Take your image example.
if my parent container changed size, that 45.6% of the parent's height could be very very wrong.
furthermore, i would have to hand-code each fragile ratio.
If i had a folder of images, that could take quite a while, and each one would have to be mentioned in the HTML.
CSS implementations vary a great degree in capability, applicability, and reliability.