After watching one of the dev log videos for Limit Theory, I wanted to duplicate his screenshot functionality.
Basically after pressing the screenshot key a nicely framed window displayed the screenshot and offered "Confirm" and "Delete" buttons.
I whipped this up in my Unity 5.2 but honestly there's no reason it should't work all the way back to Unity 3D 4.6 (<- completely untested mind you).
You can download the unity package right HERE.
Here is what it looks like in action:
Package has an Instructions.txt file along with prefabs.
Do let me know if you find it useful.
Current version 1.0