title: iPhone screenshot different colour when displayed
body: <p>I've taken a screenshot of my iPhone app running and I'd like to use that image as a png to be drawn by the app instead of generated graphics.</p>
  
  <p>When I take the screenshot, it looks fine. However, when that is saved as a PNG file, added to the Xcode project and then displayed back on the screen of the phone (or simulator) the colours are different.</p>
  
  <p>Can anyone explain to me why it's changing? (I'm guessing there's a colour space conversion happening).</p>
  
  <p>How can I stop this from changing?</p>