using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public Texture btnTexture;
    void OnGUI() {
        if (!btnTexture) {
            Debug.LogError("Please assign a texture on the inspector");
            return;
        }
        if (GUI.Button(new Rect(10, 10, 50, 50), btnTexture))
            Debug.Log("Clicked the button with an image");

        if (GUI.Button(new Rect(10, 70, 50, 30), "Click"))
            Debug.Log("Clicked the button with text");

    }
}