Mixed PNG (and Other PNG-Related Stuff)

I have an image, 'image.png'. This PNG is half opaque (50%) and the other half opaque (100% or not opaque at all). As an image in my code, this is fine, but I am using it as a background of a div. Now, the PNG has an opacity of 100%. I heard that as a background, you must set the PNG's opacity with code. But then what is the point of a PNG?

My two questions are: Can I get a PNG to be a background of a div with opacity and without using code? and Can this same PNG be half opaque and half not?

PNGs are loaded in the same way in backgrounds. If you have 100% opacity all of a sudden, you're probably being fooled by a colored/white background. Link?

Hmmm. It works now. I had to use a style sheet instead of putting it in the HTML markup.