The border effect adds a flat-color border around an image.
Border Size
Use the Narrow/Wide slider to adjust the thickness of the border.
Border Color
Use the Border Color... button to select a color for the border.
Inner Border
Check the Inner Border checkbox to display a secondary border. The Inner Border controls work the same way as the outer border controls.

Rounded Corners
Check the Rounded Corners checkbox to round out the corners of the border(s). Use the Sharp/Round slider to adjust the radius of the rounded corner.
Display Shadow
Check the Display Shadow checkbox to make the first border cast a shadow against the inner border. The inner border will cast a shadow against the image.