Round cornered images in Paint.NET

Skyline gondola I’ve been experimenting with doing some simple image post processing for my posts. Rectangular images with sharp right-angled corners look a bit stark. I’m getting most of the images from iStockphoto (referral link), and it seemed a waste if I didn’t fit photos and text together nicely.

The easiest and fastest way to spruce up a stock photo is to create round corners in the image. I’ll be showing you how to do so in the freely available, fantastic and awesome image editor, Paint.NET (did I mention it was free?).

So, suppose here’s the original photo, after loading it into Paint.NET
Original picture

Then you add a new layer by either clicking [Layers] -> [Add New Layer] option
Add new layer by option
or click on the “Add New Layer” button in the “Layers” panel (placed near bottom right by default)
Add new layer by button in layer panel

Next, you want to focus on the 2nd layer for some editing first. On the “Layers” panel, uncheck the “Background” image.
Focus on layer 2

On the 2nd layer, we wash it over with white colour first, because by default it’s in “transparent” colour. We can talk about the difference between white and transparent some other time… We’ll use the paint bucket tool
Paint bucket
By default, if you haven’t changed the colour selection yet, then the primary colour is black and the secondary colour is white.
Primary and secondary colour selection
What this means is if you click and draw with the left mouse button, black is used. If you click and draw with the right mouse button, white is used.

So after selecting the paint bucket tool, go somewhere in the (transparent-coloured) image, and right-click. This will give you a nice clinical white patch.

We want to draw a rounded black rectangle on this white patch. We use the aptly named “Rounded Rectangle” tool
Draw rounded rectangle with filled shape
Some finger nimbleness will be needed here. Our test image is 160 pixels wide and 110 pixels tall. We’ll have to left-click (for black) in the image, at the cursor position of 0,0 and drag-move to cursor position 159,109. You can find out the cursor position by looking somewhere near the bottom of Paint.NET
Cursor position
We’re at cursor position 11,9 in this case.

You should then get this beauty
Black and white rounded corner

After that, go the “Layers” panel, and click on properties for the 2nd layer
Layer properties
and set the blending mode to “Additive”
Set additive blending mode

Check the “Background” layer back (to make it visible again) and you should see this
Skyline gondola

Save and you’re done!

I think a video tutorial would have done a better job. Anyone want to sponsor the Camtasia software for me?

PS. That “Skyline gondola” sign was taken at the halfway point on my practically vertical climb up the hill in Queensland, New Zealand. I was the only one (stupid enough) climbing up. Everyone else was going down… A story for another time perhaps…

[UPDATE: Use this plugin RadiusFillCorners. Much easier if you don’t mind a bit of jaggedness on the corners. But not noticeable on larger images.]