flex air filemode read external file
protected function main():void{
var file:File = File.applicationDirectory.resolvePath( "logo.png" );
var stream:FileStream = new FileStream();
stream.open( file, FileMode.READ );
var logo:String = stream.readUTFBytes( stream.bytesAvailable );
}

<mx:Image includeIn="login" x="208" y="195" id="logo" height="248" source="{logo}"/>