title: How to test if a TImage has a graphic assigned to it?
body: <p>There's a TImage component on a form in my program. </p>
  
  <p>In some situation, the program must test:</p>
  
  <p>If "there is an image assigned to the picture property of the TImage component" then ...</p>
  
  <p>How can I do this?</p>