GunSystem/Assets/Script/Effect/ImageChange_.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class ImageChange_ : MonoBehaviour {
    public bool ischange;
    public Image self_;
    public Sprite highLightStatus;

	// Use this for initialization
	void Start () {
        ischange = false;
        StartCoroutine(ChangeImageAction());
	}

    IEnumerator ChangeImageAction() {
        while (!ischange) {
            yield return new WaitForEndOfFrame();
        }
        self_.sprite = highLightStatus;
        yield return null;
    }
    public void SetChange() {
        ischange = true;
    }
}