Actually lol, there's an even easier way to do the one pixel border. Ctrl+Shift+N to make a new layer on top of it all, then press Ctrl + A to select all, then go to Edit - Stroke, 1px (or higher if you want), select your color, then under Location, select center. Ctrl+Shift+N to make a new layer. Ctrl+A to select all Edit > Stroke > 1px (or more if you want it thicker), Select color, Location: Center, Press okay and your done! Also say you want 1px black, 1px white, 1px black. Do all that I said, then grab the magic wand tool and click anywhere within the canvas, then add the stroke hit okay, then use the magic wand tool again and click, then change it back to black.