Make an on/off toggle button.

	// Draws 2 toggle controls, one with a text, the other with an image.
	var aTexture : Texture;
	
	private var toggleTxt : boolean = false;
	private var toggleImg : boolean = false;
	
	function OnGUI () {
		if(!aTexture) {
			Debug.LogError("Please assign a texture in the inspector.");
			return;
		}
	
		toggleTxt = GUI.Toggle(Rect(10, 10, 100, 30), toggleTxt, "A Toggle text");
		toggleImg = GUI.Toggle(Rect(10, 50, 50, 50), toggleImg, aTexture);
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public Texture aTexture;
    private bool toggleTxt = false;
    private bool toggleImg = false;
    void OnGUI() {
        if (!aTexture) {
            Debug.LogError("Please assign a texture in the inspector.");
            return;
        }
        toggleTxt = GUI.Toggle(new Rect(10, 10, 100, 30), toggleTxt, "A Toggle text");
        toggleImg = GUI.Toggle(new Rect(10, 50, 50, 50), toggleImg, aTexture);
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public aTexture as Texture

	private toggleTxt as bool = false

	private toggleImg as bool = false

	def OnGUI() as void:
		if not aTexture:
			Debug.LogError('Please assign a texture in the inspector.')
			return
		toggleTxt = GUI.Toggle(Rect(10, 10, 100, 30), toggleTxt, 'A Toggle text')
		toggleImg = GUI.Toggle(Rect(10, 50, 50, 50), toggleImg, aTexture)