title: Animation on button using images
body: <p>I have a UIButton which has arrow kind of blue image set as</p>
  
  <pre><code>     UIImage *arrowImage = [UIImage imageNamed:@"bluearrow.png"];
      [self.prevbutton setBackgroundImage:arrowImage forState:UIControlStateNormal];
  </code></pre>
  
  <p>Now I have another image yellow.png, that I want to super impose on top of this button image and make a flashing animation continuously. How can I do this?</p>