You can also do the following
1. place a rectangle on the photo where you want the border
2. Set the fill to none
3 Click the Pen tool and adjust the width setting to create the border
Here is one method, there are others:-
1. Crop photo as desired and select rasterise and trim.
2. Turn snapping on
3. Draw a rectangle exactly over your cropped photo.
4. Go to transform studio, make sure the Width and height padlock is locked
5. Make sure the anchor is selected as the centre dot
6. Click on width and type “x1.1” and then ok
7. In layers studio drag rectangle to the bottom of the layer stack.
