Whoa, meant to respond to this sooner.
You probably know much more about raster graphics in Flash then me. Can we smooth that out at all and/or get the graphics to scale to an integer multiple? A 1x screenshot from CT is 256 x 224, I believe.
I'm all for not using the CT gray-box-pops-up-and-obscures-25%-of-the-screen method of showing dialogue. Doing it like you have it is fine.