How to properly give Image source for multiple sources?

I'm writing a script to change the image on the button based on previous selection. Another script is giving the CurrentAvatar variable once previous button is pressed.

My problem is i can't seem to load an image for the button using:

AvatarSprite = Resources.Load<Sprite>("Assets/Images/FireMonsters/Lamor_Icon");

Could someone please enlighten me on the proper code?

All from assets, or is it even possible?

Also looking to have multiple options in if statements, don't know a better method.

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

public class SelectedAvatar : MonoBehaviour {

    Button CurrentHeroSprite;
    static Sprite AvatarSprite;
    public static string CurrentAvatar;

    // Use this for initialization
    void Start () {
        CurrentHeroSprite = GetComponent<Button>();
    }

    // Update is called once per frame
    void Update () {
        if (CurrentAvatar == "Lamor") {
            AvatarSprite = Resources.Load<Sprite>("Assets/Images/FireMonsters/Lamor_Icon");
            CurrentHeroSprite.image.sprite = AvatarSprite; 
            Debug.Log ("loaded sprite for Lamor");
        }
        //if etc etc etc
    }
}