Quick Method of Adding a Border or Keyline to an Image on Photoshop
Sometimes adding a white, or black, or other colour border around an image can enhance the final effect.
This method is a quick and easy way to do so in Photoshop (any version).
---
1) Load your image into Photoshop (From Lightroom use 'Edit In Photoshop)
2) Goto Image on the top menu, and then Canvas Size.
3) Check the Relative box and then enter the desired width of the keyline in the Width and Height boxes. (This can be any size but for a 1920 picture around 10-15 pixels can look nice - you will need to experiment)
At the bottom under Canvas Extension Colour, select the colour you want (defaults to white).
4) Click OK, and the border will be displayed around the image.
5) Now you need to resize the image because it is a little too big. Goto Image again and then Image Size
6) Select 1920px for the longest side and click OK
7) Export as JPG as usual or Save to re-load into Lightroom.
You should now have a correctly sized image with a keyline around.