AS3 Loader ignoring .png transparency

Question

In Flash CS4, open a new document, change the background colour to something recognizeable (like magenta) and add the following code:

var loader:Loader = new Loader();
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, function(e:Event){addChild(e.target.content);});
loader.load(new URLRequest('newsnakelub8.png'));

... replacing the .png filename with any you happen to have handy, I grabbed this one. Compile the .swf, and join me in a sigh of disapointment - the normally transparent .png now has a white background, not allowing the flash background colour to show through.

Is there a magical 'treatAsPNG24' property that I'm missing somewhere?

Answer 1

The problem is your png. Try opening it in Photoshop and it won't be transparent there either. Try a different one - google it, or publish one from Flash or PS - and it will work fine. (That is, there's no setting to invoke, you just need a proper image.)

Answer 2

Since it's better to teach you how to fish...

If you're using GIMP 2 (free as in beer), just open the image, select Layer | Transparency... | Color to Alpha and pick the color you want to be converted to the transparent background.