title: What's the difference between setBackgroundImage:Forstate and setImage:Forstate:
body: <p>I am trying to set a image for a UIButton.</p>
  
  <p>I don't know the difference between the setBackgroundImage:Forstate and setImage:Forstate:</p>
  
  <p>Could anyone help me out? </p>
  
  <p>Thanks and best regards.</p>