Referencing an array but its returning a nullrefrence exception?

So this one is really strange... I am attempting to create an armor system that shows up visually, and to do so I have this script that stores what armor is equipped (In an array public currentEquipment[])and then sets the images to the corresponding icons of the items in the array. (The objects in the array are scriptable "equipment" objects. And while this code lets the game continue running, it spits out a nullrefrence exeption every frame on all the armor images in the UI that dont have a armor object assigned to them. (The 'equipment' items all have a sprite associated with them that can be referenced other places just fine.) I am very very confused and I have no idea why 1.) Im getting these errors, 2.) why the game is still running despite these errors. (Ps. the error is on every line of void Update() where currentEquipment[] is called.)

Here is the code:

 #region singleton
 public static EquipmentManager instance;

 void Awake()
 {
     instance = this;
 }

 #endregion


 public Equipment[] currentEquipment;

 public Image Head;
 public Image Body;
 public Image Legs;
 public Image Charm;

 Inventory inventory;

 void Start()
 {
     inventory = Inventory.instance;

     int numSlots = System.Enum.GetNames(typeof(EquipmentSlot)).Length;
     currentEquipment = new Equipment[numSlots];

     Head.enabled = false;
     Body.enabled = false;
     Legs.enabled = false;
     Charm.enabled = false;

 }

 public void Equip(Equipment newItem)
 {
     int slotIndex = (int)newItem.equipSlot;

     Equipment oldItem = null;


     if(currentEquipment[slotIndex] != null)
     {
         oldItem = currentEquipment[slotIndex];
         inventory.Add(oldItem);
     }

     currentEquipment[slotIndex] = newItem;
 }

 void Update()
 {
     if (currentEquipment[0].icon != null)
     {
         Head.enabled = true;
         Head.sprite = currentEquipment[0].icon;
     }
     else
     {
         Head.sprite = null;
         Head.enabled = false;
     }

     if (currentEquipment[1].icon != null)
     {
         Body.enabled = true;
         Body.sprite = currentEquipment[1].icon;
     }
     else
     {
         Body.sprite = null;
         Body.enabled = false;
     }
     if (currentEquipment[2].icon != null)
     {
         Legs.enabled = true;
         Legs.sprite = currentEquipment[2].icon;
     }
     else
     {
         Legs.sprite = null;
         Legs.enabled = false;
     }
     if (currentEquipment[4].icon != null)
     {
         Charm.enabled = true;
         Charm.sprite = currentEquipment[4].icon;
     }
     else
     {
         Charm.sprite = null;
         Charm.enabled = false;
     }

 }

}