I just threw in some handy photos.  I was using Photoshop Elements 12 and couldn't find an inner (forgot the name).  I switched to Outer and resized the boxes so that the outer boarder could fit and dropped a blank white background under everything.  Otherwise, all the instructions did work but it took me quite awhile to figure out why I wasn't seeing a border around the photos.  It took more adjustment and the pixel counts somehow didn't add up.  I can only assume that some of the snap-to features and lack of rounding may have left a decrepency but zooming in after figuring out the borders helped the snap-to feature work.