Deactivate GameObject and Image on NGUI button

I'm a novice programmer and need some advice. I got my current code working correctly, but I have noticed a problem. Since my code is attached to a Gui button, I got my gameobject and images to activate / deactivate correctly, however, if I pressed on another NGUI button, the gameobject doesn't disappear when I select a different button. I also noticed the images remain hidden when I go return to the subject matter. I know i can deactivate the gameobject on the Onclick, but I think there got to be a better and way of activating and deactivating gameobject and images. I have attached an image on the bottom. Any suggestions?

    #pragma strict
     var images : Texture2D[];
     var i : int = 0;
     
     var showImage = true;
     
     public var objectToHide:GameObject;
     public var hideBeforeShow:boolean=true;
     
     function Start(){
     
         if(hideBeforeShow == true){
             
             objectToHide.SetActive(false);
         }
     }
     function OnGUI () {
     
         if (showImage)
             GUI.DrawTexture(Rect(365,20,1500,900),images[i]);
       
         if (GUI.Button(new Rect(880,930,100,50),"PREVIOUS"))
         {
             if (i > 0)
                 i--;
             GUI.DrawTexture(Rect(200,50,100,100), images[i]);
             print(i);  
     
             showImage = true;
             objectToHide.SetActive(false);
         }
     
         if (GUI.Button(new Rect(1000,930,100,50),"NEXT"))
         {
             if (i < images.Length - 1)
                 i++;
      
             GUI.DrawTexture(Rect(200,50,100,100), images[i]);  
             print(i);
     
             showImage = true;
             objectToHide.SetActive(false);
         }
     
         if (GUI.Button(new Rect(1120,930,100,50),"3D MODEL"))
     
         {
             showImage = false;
             objectToHide.SetActive(true); 
         }
     }

[1]: /storage/temp/57027-screenshot.jpg