Error 'ScaleX' is not a member of 'UnityEngine.Texture2D' (help!)

Hello - I want my health bar to decrease proportionately with the amount of player vitality. However I can't seem to link the player's health to the health bar correctly - on using this code which seems to have worked for some people I have been given this error, and I just can't work out how to change it.

Here's the code:

 var energyBar : GUIStyle ;
  
 var bgImage : Texture2D; 
 var fgImage : Texture2D;
 static var playerEnergy = 1.0; 
 
 var maxHealth : float = 100;
 var curHealth : float = 100;
 var percentHealth : Number = curHealth / maxHealth;
 
  
 function Start() {
 
 }
  
 function Update() {
 
 }
  
 function OnGUI () {
 GUI.BeginGroup (Rect (10,10,256,32));
  
 GUI.Box (Rect (0,0,256,32), bgImage, energyBar);
  
 GUI.BeginGroup (Rect (0,0,playerEnergy * 256, 32));
  
 GUI.Box (Rect (0,0,256,32), fgImage, energyBar);
  
 GUI.EndGroup ();
 GUI.EndGroup ();
 }
 
 function updateHealthBar () : void
 {
 percentHealth = curHealth / maxHealth;
 fgImage.ScaleX = percentHealth;
 }

If anyone has the time to help, it would be so appreciated.

Thanks in advance, Laurien