I hadn't noticed this menu option before until I worked on my recent layout and played with it. It's called "Border" and you'll find it under the "Grow" option on the Select menu.
Some simple instructions as follows:
1. Select photo layer, do Alpha to Selection,
2. Create new transparent layer,
3. Ensure that new layer is selected now, go to Select menu > Border, In pop-up window set border size to your liking,
4. Edit menu > Fill with BG color (default is set to white),
5. Add dropshadow layer if you wish and you are done.
6. To deselect the moving dots, you can do via the Edit menu or a shortcut is Ctrl+Shift+A.