A Word in Your Shell Like

John Gravett's youtube tutorials are great, but like all of the Ps tutorials you have to read between the lines sometimes.  
John goes into great detail about how the white guidelines in the outer border of the grid should be placed inside and not centre.  (Also, preferences in a MAC is not under edit, but under the Photoshop header as normal.) This led me to believe that it was these white guidelines that created the white border around each picture in the completed Orb Mosaic and I couldn't get it to work.  Never assume - check!  It took me a while to realise that the pictures he was placing in the collage template had a white border on them. Back to youtube for a tutorial on how to batch prepare and export photos from LR with a border.  
In this Orb I have chosen a 2px wide border that is black.  If you put a non-descriptive picture with a narrow white border in the centre of the template then the whole Orb will have a white border.
Notwithstanding all of this, I reiterate that John's tutorials are well presented and worth watching