Choose an image. I'll be using this one:
Now open a new image. Go to File » New. Make your new selection a bit bigger than the picture you already have open. Just to be safe, I always set mine to a rediciously big size. For now I set mine 500x500. Make sure you make it TRANSPARENT!!.
Now using your Rectangle tool, select the entire first image. Go to Edit » Copy.
On your new, transparent image, go to Edit » Paste. Next, go to Layer » Layer Style » Drop Shadow. Then click 'Stroke' on the left. Make the stroke color whatever you wish, and set the stroke size to 1 or 2px. Now, Go click on 'Bevel & Emboss'.
Lastly, using the cropping tool, crop the image down to an appropriate size. Save it as a .PNG & you're done!!
