title: Change background image of a button without extra buttons
body: <p>I've set a button with an image as it's background, and I'm trying to get the image to change back and forth from 2 different images when pressed. 
  For example, a happy face when pressed would switch to a sad face, and when pressed again would switch back to a happy face and so on.</p>
  
  <p>Any help you can offer would be amazing before I pull anymore hair out.</p>