Add an an array of images to use in dialogue box

Currently i have a dialogue box setup, but i’d like to add an image of the character that was clicked on to the dialogue box. This is what i have. Please help, not sure what the best way to approach this is.
DialogueManager

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

public class DialogueManager : MonoBehaviour
{
    public GameObject dialogueBox;
    public Text dialogueText;
    public bool dialogueActive;
    public string[] dialogueLines;
    public int currentLine;
    public Image Character;
    public Sprite[] CharacterImages;
    public int currentCharacter;


    void Start ()
    {

	}
	
	void Update ()
    {
        if (dialogueActive && Input.GetButtonDown("Fire2"))
        {
            currentLine++;
            currentCharacter++;
        }

        if (currentLine >= dialogueLines.Length)
        {
            dialogueBox.SetActive(false);
            dialogueActive = false;
            currentLine = 0;
            currentCharacter = 0;
        }

        dialogueText.text = dialogueLines[currentLine];

    }

    public void ShowDialogue()
    {
        dialogueActive = true;
        dialogueBox.SetActive(true);
    }
}

using UnityEngine;
using System.Collections;

public class DialogueHolder : MonoBehaviour
{
public string dialogueLines;
public Sprite CharacterImages;

private DialogueManager DialogueManager;

void Start ()
{
    DialogueManager = FindObjectOfType<DialogueManager>();
}

void Update ()
{

}

void OnTriggerStay2D(Collider2D other)
{
    if (other.gameObject.name == "Player")
    {
        if (Input.GetButtonUp("Fire2"))
        {
            if (!DialogueManager.dialogueActive)
            {
                DialogueManager.dialogueLines = dialogueLines;
                DialogueManager.currentLine = 0;
                DialogueManager.ShowDialogue();
                DialogueManager.CharacterImages = CharacterImages;
                DialogueManager.currentCharacter = 0;
            }
        }
    }
}

}

It’s a 2D RPG game. The character moves into the NPCs trigger Zone (dialougeHolder) then i press the space bar to display the dialog box. Where the white bowx is on the left I would like to display the picture of the NPC the Player is talking to.