Border dialog box
Image Effects dialog box – Border button
Width
Enter the width of the frame from 1 to 100 pixels.
Roundness
Enter the radius of the Roundness from 1 to 100 pixels. Higher the number, more rounded the corners will be.
Color
Specify the color of the frame.
Preview
You can preview the result the in the preview pane on the right. If the image is too big to fit in the window, drag to move the image in the preview pane to view a specific part of the image.
+, – button
You can increase of decrease the magnification of the image in the Preview window using these buttons.