gistfile1.as

/*
	import flash.display.*;
	import flash.utils.*;
	import mx.graphics.codec.*;
*/

var bitmap:BitmapData = new BitmapData(128, 128, true);
var x:int, y:int;
for (y = 0; y < bitmap.height; y++) {
	for (x = 0; x < bitmap.width; x++) {
		bitmap.setPixel32(x, y, Math.random() * 0xFFFFFFFF);
	}
}
var encoder:PNGEncoder = new PNGEncoder;
var raw:ByteArray = encoder.encode(bitmap);
var file:FileReference = new FileReference();
file.save(raw, 'saveme.png');