Removing redeye used to be a major requirement for digital photographers, but these days newer sophisticated cameras can minimise it when you take the picture. But for those of you who want to have a go, Paint.net has a Redeye Removal Tool, albeit fairly unsophisticated..
For this task, we'll use the picture of two young children.
First of all open the 'twokids' image.
Next, as with the cloning task, you should zoom in on the image to help you work with the detail.
Zoom in on the girl's face as shown, using the zoom tool.
Step 2 - Use the Elipse selection 
Tip: Before applying the Redeye Removal, you should select all the eyes in the picture.
This is done by choosing the Elipse selection tool (arrowed) and making sure that the Selection Mode (at A) is set to Add (union).
With the tool set, highlight each of the eyes (arrowed at A), then use the Hand tool (arrowed with the thick arrow) to move the image around to include the little boy, then select his eyes. You may need a little practice using the elipse tool.
Note that, if you make a selection you are not happy with, you can 'overwrite' that selection just by making a new one over or next to the first one.
If you want to remove selections there are various ways:
The first is to 'step back' to a point before the last selection by using the History palette (press F6 to show it).
All selections can be removed by using the menu command: EDIT > DESELECT (CTRL + D).
You are now ready to use Redeye Removal. To invoke it use the menu command: EFECTS > PHOTO > REDEYE REMOVAL.
When the dialogue box comes up, my recommended setting for this picture are:
Tolerance: around 10 to 15
Saturation: around 25
You are at liberty to experiment with these settings. A higher saturation value will increase the intensity of the pupil color. The effect will be previewed on the image as you use the sliders.
Finish and use Save As to save the image with a new filename.