title: Necessary to have non-hd file?
body: <p>I am developing for iPhone 4 retina display using Cocos2d.</p>
  
  <p>Well, I enabled retina display, and I have only put -hd graphics in my project. But when I run the project, it tells me that the -hd files are not found!</p>
  
  <p>Then, I, for the sake of testing, put non-hd versions in the project. And apparently I don't get the error anymore.</p>
  
  <p>This is puzzling. Does it mean I am forced to have -hd and non-hd versions in all my retina-enabled projects?</p>