how do you change a raw image in unity using c#

I am trying to make a main menu in unity with multiple images problem is i cant figure out how to go about creating code to change the image when you hover over the button with your mouse.

here is my code:

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

public class imagechange : MonoBehaviour
{
    [SerializeField] private Image newimage;
    [SerializeField] private Image oldimage;

    private void OnMouseEnter()
    {
        //this will change the image from not hovered to hovered
        newimage.enabled = true;
        oldimage.enabled = false;
    }

    private void OnMouseExit()
    {
        //this will change the image from hovered to not hovered
        newimage.enabled = false;
        oldimage.enabled = true;
    }
}

i cant get the images into the variables so I can change the image.

Good Day.

You should check this post or this UnityAPI page.

Accept the answer or close the issue :D