How do i set screenshot image of Scene2 to Scene1(Button) in unity. Thanks in adavance

After winning the game i want to set my Level-1 screenshot image to Button1 if i get reply i will be very gratefull to you.

Well, assuming you’re using Unity’s UI system and a canvas, you can set it through code with something along the lines of the following (if you have a script of some kind to cater).

using UnityEngine.UI;

public Sprite scene1Sprite;

//Will require you to throw this line into where you're checking you've finished and set to high-score scene.
public void CalledWhenHitLevelChange()
{
    GameObject.Find("Button1").GetComponent<Image>().sprite = scene1Sprite;
}

Basic, of course, and mostly pseudocode. You should check out the documentation. If you have any more questions, don’t hesitate to PM me.