title: how do i detect a multi-layered psd file using imageIO.framework?
body: <p>i don't want to extract or use the multi-layer information, i want to report to the user that it can't be imported. i'm creating specific-sized jpgs from imported files, and the user needs to decide how to flatten that multiple-layered file according to her aesthetic. </p>
  
  <p>the only reference to multilayered i see is <code>CGImageSourceGetCount(CGImageSourceRef)</code> </p>
  
  <blockquote>
    <p>If the image source is a multilayered PSD file, the function returns 1.</p>
  </blockquote>
  
  <p>which, of course, isn't helpful in my case.</p>