So you want to do rounded corners using Paint.NET? You must learn how. I mean your web site would be so not in style without images with rounded corners! I’m going to show you the easiest method I know about. I think it’s easier than using Photoshop to do it.

Here we have a nice picture of downtown Chicago. I want to give it rounded corners.

First I want to add a new layer by clicking Layers > Add New Layer.

Now select the Rounded Rectangle Tool. The color doesn’t really matter.

In the upper left corner, select to Draw Filled Shape.

Draw the rounded rectangle over the area you would like to keep for your rounded corners image.

Use the Magic Wand to select the area of the rounded rectangle.

Click Edit > Invert Selection.

Now the area outside of the rounded square will be selected.

Select Layers > Delete Layer to delete the layer we made our rounded square on.

The area outside of the rounded square will still be selected.

Simply press Delete on your keyboard and you are left with your image, now with rounded corners.