public void DifferenceBlendOp2 ()
		{
			var lhs = GetSourceImage ("blend1.png");
			var rhs = GetSourceImage ("blend2.png");

			var lhs_wrap = new BitmapWrapper (lhs);
			var rhs_wrap = new BitmapWrapper (rhs);

			var op = new DifferenceBlendOp ();
			op.Apply (rhs_wrap, lhs_wrap);

			Compare (lhs, "differenceblend2.png");
		}