Trouble toggling Raw Image script component inherited from Canvas upon mouse click

I attached a script (ClickMe) under the Raw Image container object under Canvas. My goal is to reveal/hide (toggle) the image on canvas by enabling/disabling the raw image script. I seem to have trouble re-enabling the image after disabling it.

Any clue as to why that happens would be appreciated! Thanks!

using UnityEngine; using UnityEngine.UI; using System.Collections; using UnityEngine.EventSystems;

public class ClickMe : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler, IPointerClickHandler {

 public RawImage tileImage;

 // Use this for initialization
 void Start () {
     tileImage = GetComponent<RawImage>();
 }
 
 // Update is called once per frame
 void Update () {

     // it works when I update every frame
     /*
     if (Input.GetMouseButtonDown (0)) {
         Debug.Log ("Mouse Down");
         tileImage.enabled = !tileImage.enabled;
     }
     */

 }

 public void OnPointerEnter(PointerEventData eventData)
 {
     Debug.Log ("On Enter Pointer");
 }

 public void OnPointerExit(PointerEventData eventData)
 {
     Debug.Log ("On Exit Pointer");
 }
     
 public void OnPointerClick(PointerEventData eventData)
 {
     Debug.Log ("On Click Pointer");
     tileImage.enabled = !tileImage.enabled;    // Can't enable after disabled
 }

}