GUI.button Texture shows up in Unity but doesn't show on android device.

Hi,

I am trying to make a pause button and put it on the top left corner of my game.

So I did:

 Texture2D pauseImage= (Texture2D)Resources.LoadAssetAtPath("..../somepic.png", typeof(Texture2D));
 private GUIStyle clearStyle = new GUIStyle();
 
 if (GUI.Button(new Rect(0, 0, 60, 60), pauseImage, clearStyle)) {
     isPause = !isPause; 
 }

My button shows up and works fine in the Unity simulator. But when I deploy the game to my phone, the button become invisible and the image of the pause button is not loaded. I am wondering what could be the cause of this?

Thanks in advance.