So I have layered some transparent pngs on top of another image and of course in IE, these pngs don't show up as being transparent. I've tried changing the images to GIFs but then the edges of the images pixelate and I don't know how to fix it.

I am already using an IE hack and all the other transparent PNGs are working, I just concluded that these aren't working because they're positioned on top of another image.