Change size of image loaded as URLRequest

I want to display a callout box that has a title bar. I’ve created “chunks” of the callout box with images that I will assemble once loaded: A chunk of the titlebar, the left corner of the title bar, the right corner, the borders, etc. Each of these chunks is a .swf file that I’m loading with a URLRequest from my Callout class.

My problem is that, once I get the images loaded, I want to be able to change their size as well as position them. For example, I want to make the callout as wide as an argument I pass to the Callout class, so I need to change the width of the title bar image.

Positioning is no problem. But, because the titlebar image is loaded the way it is, it has zero width, and that width cannot be changed.

I have tried creating a container sprite for the image, and changing the width of the container, but that doesn’t work either.

How do I do this? I’m thinking that maybe the Loader var that brings the image in can be cast as a Sprite or something, but I don’t know how to do that.

Many thanks!