title: Standalone CKFinder: how to only select images in file dialog popup?
body: <p>I'm using CKFinder in combination with CKEditor, but also as standalone file input image popup window. So when someone clicks the "upload"-button, a new popup window appears in which someone could select an image / file / Flash-file to upload.
  For the field "avatar" I need to only select image files. It shouldn't be possible to select  another filetype. How can I get this working? In the documentation I can't find very helpful information.</p>
  
  <p>In CKEditor it's possible to only select an image or a file from within the CKFinder-popup, but it looks like the same option has been forgotten in the standalone version of CKFinder.
  I need to achieve "ckfinder.html?type=Image", but I don't want to modify ckfinder.js because that will affect also other file popup dialogs in which someone should be able to select even images as files.</p>
  
  <p>I'm including CKFinder like in the popup sample:</p>
  
  <pre><code>var finder = new CKFinder();
  finder.basePath = '../';    // The path for the installation of CKFinder (default = "/ckfinder/").
  finder.selectActionFunction = SetFileField;
  finder.popup();
  </code></pre>
  
  <p>Thanks in advance for your help!</p>