Sprite change on click

I have a list of character sprites. I want them changed by clicking the mouse. The problem is that they change but еру previous sprite want disappear and they overlap on top of other. There are 2 scripts that I wrote

 using UnityEngine;
 
 public class change : MonoBehaviour {
 
 
 
 
     public static int counter = 0;
     public string resourceName = "Characters";
     public Sprite[] characters;
     SpriteRenderer currentSprite;
 
 
 
     void Awake()
     {
         if (resourceName != "")
         {
             characters = Resources.LoadAll<Sprite>(resourceName);
         }
     }
     // Use this for initialization
     void Start () {
         currentSprite = GameObject.Find("Character").GetComponent<SpriteRenderer>();
 
 
     }
     
     // Update is called once per frame
     void Update () {
         if (Input.GetMouseButtonDown(0) && counter < characters.Length)
         {
             if (currentSprite.sprite == null)
             {
                 currentSprite.sprite = characters[counter];
                 currentSprite.enabled = true;
                 counter++;
             }
             else
             {
                 currentSprite.sprite = null;
                 currentSprite.enabled = false;
             }
             
         }
         
 
     }
     
 }

this is the result:

and the second

 using UnityEngine;
 using System.Collections;
 
 public class destroy : MonoBehaviour {
 
     static int counter = 0;
     string resourceName = "Characters";
     Sprite[] backgrounds;
     GameObject character;
     SpriteRenderer currentSprite;
 
 
 
     void Awake()
     {
         if (resourceName != "")
         {
             backgrounds = Resources.LoadAll<Sprite>(resourceName);
         }
     }
     // Use this for initialization
     void Start()
     {
         character = GameObject.Find("Character");
         
 
     }
 
     // Update is called once per frame
     void Update()
     {
         if (Input.GetMouseButtonDown(0) && counter < backgrounds.Length)
         {
             if (!character.GetComponent<SpriteRenderer>())
             {
                 character.AddComponent<SpriteRenderer>();
                 currentSprite = character.GetComponent<SpriteRenderer>();
                 currentSprite.sprite = backgrounds[counter];
                 counter++;
             }
             else
                 Destroy(character.GetComponent<SpriteRenderer>());
 
 
         }
 
 
     }
 
 }

Help please.