add a picture frame

For a quick line border in PP that doesn't add extra width to my image, I use the Rectangle tool.

1. First, turn on Snap to Grid on the View menu.
2. Next, change the grid divisions to match your image (e.g. if your image is 800px x 600px  then make the divisions 100 x 100).
3. Choose the Rectangle tool and on its property bar change the fill option to No Fill, type in your desired outline width, select your color, and choose to place it on a new layer.
4. Starting at one corner of the image and draw the rectangle diagonally to the opposite corner (it will snap in place).. 
5. If you are happy with it, combine the "frame" layer with the image layer.
6. Done. Takes much longer to type out the instructions than to actually do it.

Patti