Resize GUI for older iPhone versions

Hey guys, I'm working with an iPhone 4. The native resolutio is 960*640.

Now I am a bit struggling with the resizing of GUITextures for older iPhone models.

I found in another answer this code:

function OnGUI () {
GUI.Box (Rect (0,0,100,50), "Top-left");
GUI.Box (Rect (Screen.width - 100,0,100,50), "Top-right");
GUI.Box (Rect (0,Screen.height - 50,100,50), "Bottom-left");
GUI.Box (Rect (Screen.width - 100,Screen.height - 50,100,50), "Bottom-right");

and it works. But how can I do the same with GuiTextures instead of Gui Boxes?

I found in another post this code:

public float native_width = 960;
 public float native_height = 640;
 void OnGUI()
     if(Application.platform == RuntimePlatform.IPhonePlayer)
         float actual_height = Screen.height;
         float actual_width = Screen.width;
         float ry = actual_height / native_height;
         float rx = actual_width / native_width; 
         GUI.matrix = Matrix4x4.TRS (new Vector3(0, 0, 0), Quaternion.identity, new Vector3 (rx, ry, 1)); 
      // your GUI code here


If you want simple scale then you can set the matrix like this at the beginning of your OnGUI function:

GUI.matrix = Matrix4x4.TRS(, Quaternion.identity,new Vector3(Screen.width / 640.0f, Screen.height / 960.0f, 1));

In this case your GUI will scale down accordingly

You only need to focus on one resolution (in this case 640 X 960) for your GUI work