Image Button Question

Have created a button to move the scene,
To change the image button can modify? ‘Rect’

Rect rect_000 = new Rect (50, 500, 100, 30);

    void OnGUI () {
        if (GUI.Button (rect_000, "Button0")) {
            Barrel_0.GetComponent  (). IsClick = true;
        }

You can put a texture on your GuiButton.