Thank you for your kind advices and offered solutions. Of course, there exist many ways to somehow bypass it. At least I could use a different editor. I posted this for (i) I was not able to get good results with built-in red-eye removal effect and (ii) nobody reported such problem - at least I didn't find it. There could be two reasons for it - either tool is useful and I applied it wrong way or nobody uses Paint.NET for red-eye removal. Seems to me the second reason is true.