public LayoutPartImageViewModel(LayoutPartImageProperties properties)
		{
			_imageBrush = null;
			_properties = properties ?? new LayoutPartImageProperties();
			_imagePage = new LayoutPartPropertyImagePageViewModel(this);
			UpdateLayoutPart();
		}
		public LayoutPartImageViewModel(LayoutPartImageProperties properties)
		{
			_imageSource = null;
			_properties = properties ?? new LayoutPartImageProperties();
			_imagePage = new LayoutPartPropertyImagePageViewModel(this);
		}