How to assign different texture to a GUI skin

Hello,

I'm trying to put some buttons to an interface of an application and I using different textures and dimension for each button with different function.

I don't want to show text in my buttons because I'm using symbols in the textures.

I have tried to use a texture as a button but I have to make a different Scripts for each one.

Please take a look to my script and the screenshots

Thanks in advance

 var beep : AudioClip;
 var menuSkin : GUISkin;
 var menuArea : Rect;
 
 var powerButton : Rect;
 var batteryButton : Rect;
 var keyButton : Rect;
  
 
 function OnGUI(){
 GUI.skin = menuSkin;
 GUI.BeginGroup (menuArea);
 
 if(GUI.Button(Rect(powerButton), "")){
 }
 
 if(GUI.Button(Rect(batteryButton), "")){
 }
 
 if(GUI.Button(Rect(keyButton), "")){
 }
  
  
  
 GUI.EndGroup();
 }
 function Update () {
 
 }
 
 @script RequireComponent(AudioSource)