You want rounded corners on your image. Use Adobe Fireworks CS3 to quickly apply the rounded corners. Rounded corners enhance the appearance of images in articles.
There isn't an easy way to automatically add rounded corners to your image. We will create a new rounded rectangle shape in Fireworks CS3 and then use Paste Inside to frame the image.
First find the image you want to put rounded corners around. Open it directly in Adobe Fireworks. Here's the image I will put rounded corners on.
Click on the shape tool in the palette on the left. Select Rounded Rectangle. Now swipe the mouse from the top left corner of the image to the bottom right. A rounded rectangle will cover your picture.
Note on color. The rounded rectangle may be a different color than shown. The color doesn't matter here.
In the Layers pane on the right, select the bitmap picture thumbnail. Blue bars will appear around your image. Select Edit -> Cut.
Now select the Rounded Rectangle layer. Go to Edit -> Paste Inside. Your image will now be contained in the Rounded Rectangle, giving it curved borders.
Click on the Rounded Rectangle icon in the Layers pane. Now open Window -> Auto Shape Properties. You will see the way to change how round the corners are.
Fireworks has excellent routines to make the corners look smooth. The finished images will not have any jaggies. Programs like Paint.NET do not have a good way to do this.