TowerDefense image import (eclipse,java)

I've been working on a tower defense game using eclipse and I cannot manage to print out the picture of my tower. Here is some code from the main tower class :

 `public class MainTower {    
    public String TextureFile = ""; 
    public Image texture;         

  public static final MainTower[] towerList = new MainTower[150];       

    public static final MainTower towerOfLight = new LightningTower(0).getTextureFile("Lightning");           
    public MainTower(int id)  {   
    if(towerList[id] != null){        
    System.out.println("[Tower Initialization] Two towers with the same id" + id);        

      else{           
    towerList[id] = this;         
    this.id = id;     
      }       
    }         
    public MainTower  getTextureFile(String str) {    
    this.TextureFile = str;       
    this.texture = new ImageIcon("/res/tower/" + this.TextureFile + "png").getImage();                
    return null;
      }  }

The location is correct the image is a 25x25 png image called Lightning. Here is some code from the layout class :

>     `for(int x = 0; x<15; x++){   
>               for(int y = 0; y<2; y++){           
>       if(MainTower.towerList[x *2 +y] != null)                GUI.drawImage(MainTower.towerList[x * 2 + y].texture, (int) (12 + 12 + 250 + 40 + 12 +(x * towerWidth)), (12*50) + 20 + (y *(int)towerHeight), null);               
>     
>     GUI.drawRect((int) (12 + 12 + 250 + 40 + 12 +(x * towerWidth)), (int) ((12*50) + 20  + ((y * towerHeight))),(int)towerWidth,(int)towerHeight);        
>       }     
>       }   
>       }`

I've created a grid (boxes) at the bottom of the screen where I wish to place my towers so the player can choose. So I was wondering where am i going wrong so the picture doesn't print out.