more guitexture in void ongui

you can write the full script? For example I have the images "help" and "help2" as the off / on?

 public Texture2D help1; //drag image help 1 here
 public Texture2D help2; //drag image help 2 here
 
 bool show_help1;
 bool show_help2;
 
 void Start(){
 //images wont show as default
 
 show_help1 = false;
 show_help2 = false;
 
 }
 
 void Update(){
    if(Input.GetKeyDown(KeyCode.Mouse0)){
       show_help1 = true;
    }
    if(Input.GetKeyUp(KeyCode.Mouse0)){
       show_help1 = false;
    }
 
    if(Input.GetKeyDown(KeyCode.Mouse1)){
       show_help2 = true;
    }
    if(Input.GetKeyUp(KeyCode.Mouse1)){
       show_help2 = false;
    }
 }
 
 
 void OnGUI(){
 
 if(show_help1 == true){
 GUI.DrawTexture(new Rect(Screen.width-help1.width, Screen.height/2,help1.width,help1.height),help1);
 }
 
 if(show_help2 == true){
 GUI.DrawTexture(new Rect(0, Screen.height/2,help2.width,help2.height),help2);
 }

If you will hold down left mouse button, you will see help 1 image. But on right mouse button hold you will see help2 image.

the script works ok but how do I correctly position the image at the top right of the screen?

Please read the docs before asking, i have a feeling that you are not even trying to understand. Everything you need is I already mentioned and even coded for you. http://docs.unity3d.com/Documentation/ScriptReference/Rect.html

 GUI.DrawTexture(new Rect(//distance from left screen side, //distance from upp screen side, //gui box width, gui box height), //image to show );

So to get it on top right corner:

 GUI.DrawTexture(new Rect(Screen.width - help1.width, 0 , help1.width , help1,height),help1);

And remember to accept my answer.