How to make good Reach screenshots

First off I appologize if this is the wrong forum to post in it seemed like a few of them would be appropriate for this question. Anyway my question is how people make the screenshots with the special effects that get gallery features every once in a while. I understand how people use explosions and special fx to get the vibrant colors but I want to know how to make the icy effect like the “Thin Line” screenshot in the most recent gallery, and any other tips to make good screenshots, Im asking this because now with the file share back up Id like to make a computer background for myself.