Screenshot and use it in GUITexture Script Help

This is a working script for Cature a screenshot and save it in file

after that i create a GUITexture and put the Texture to None(Texture)

when i screenshot and save,i wanted it to display it on GUITexture>can some1 help me thx i have no idea how to write it

using UnityEngine;
using System.Collections;

public class TakeScreenshot : MonoBehaviour
private int screenshotCount = 0;

// Check for screenshot key each frame
void Update()
    // take screenshot on up->down transition of F9 key
    if (Input.GetKeyDown("k"))
        string screenshotFilename;
            screenshotFilename = "screenshot" + screenshotCount + ".png";

        } while (System.IO.File.Exists(screenshotFilename));


I found a similar post have a look at this