I'm trying to set a WPF image's source in code. The image is embedded as a resource in the project. By looking at examples I've come up with the below code. For some reason it doesn't work - the image does not show up.

By debugging I can see that the stream contains the image data. So what's wrong?

Assembly asm = Assembly.GetExecutingAssembly();
Stream iconStream = asm.GetManifestResourceStream("SomeImage.png");
PngBitmapDecoder iconDecoder = new PngBitmapDecoder(iconStream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
ImageSource iconSource = iconDecoder.Frames[0];
_icon.Source = iconSource;

The icon is defined something like this: <Image x:Name="_icon" Width="16" Height="16" />