Having the same problem as Ed with the same Matt Kloskowski book:
THE COMPLETE GUIDE TO PHOTOSHOP;S MOST POWERFUL FEATURE. Page 26.
Matt is telling you how easy it is to put a stroke around a photo.
First you select the photo, then create a new layer on top of it. From the Edit menu, you choose Stroke, set the Width to 1 px, Color to White and the Location to Inside. Then deselect. Wham you see a white stroke around the photo.
Then Matt has you duplicate the stroke layer so that we can add it around two other photos. He tells us to press Command-J to duplicate the stroke layer twice, (which makes two new copies of the stroke layer) and then use the Move tool to move the copied strokes over the other two photos. This doesn't happen, a message appears: COULD NOT COMPLETE YOUR REQUEST BECAUSE SOURCE DESTINATION DOCUMENTS ARE THE SAME.
What does this mean? Literally following Matt Kloskowski's instructions as written. Can anyone help?