How I can change the sprite with resources.Load?

  private float bildRate;
  private float nextBild;
  private int counter;
  public int maxSpriteAnzahl;
  public Image pic;
  void Start()
  {
      bildRate = 0.0333333f;
      pic = GetComponent<Image>();
  }
  void Update()
  {
      if (Time.time > nextBild)
      {
          nextBild = Time.time + bildRate;
          counter++;
          spriteAufrufen();
          Debug.Log(counter);
      }
      if (counter >= maxSpriteAnzahl)
      {
          counter = 0;
      }
  }
  void spriteAufrufen()
  {
      if (counter == 1)
      {
          Sprite sprit = Resources.Load("Resources/1") as Sprite;
          pic.sprite = sprit;
          
      }
      if (counter == 2)
      {
          Sprite sprit = Resources.Load("Resources/2") as Sprite;
          pic.sprite = sprit;
          
      }
  }