title: set UIButton's image in interface builder for differen state
body: <p>I am facing very strange issue.</p>
  
  <p>In interface builder I am trying to set images for "normal" state config and for "selected" state config. but by clicking the button my image is not getting changed.</p>
  
  <p>even I write the code in viewDidLoad method.</p>
  
  <pre><code>[btnCheckBoxMale setImage:[UIImage imageNamed:@"blankcheckbox.png"] forState:UIControlStateNormal];
      [btnCheckBoxMale setImage:[UIImage imageNamed:@"checkbox.png"] forState:UIControlStateSelected];
  </code></pre>
  
  <p>but my images are not getting changed on cliking on it</p>
  
  <p>can anyboday say what is the problem?</p>