title: Accessing attachment file for meta-information
body: <p>A rails3 application with Carrierwave and <a href="https://github.com/minimagick/minimagick" rel="nofollow">MiniMagick</a> is loading files.  However in an attempt to get meta-information out it is hitting Errno::ENOENT</p>
  
  <p>The helper method</p>
  
  <pre><code>  def image
      @document = Document.find(params[:id])
      image = MiniMagick::Image.open(@document.production_file)
    end
  </code></pre>
  
  <p>is called in the view</p>
  
  <pre><code>&lt;%= image['width'] %&gt;
  </code></pre>
  
  <p>but the error is specified as</p>
  
  <pre><code>No such file or directory - /uploads/document/production_file/1/leader_pg_600.jpg
  </code></pre>
  
  <p>Yet </p>
  
  <pre><code>localhost:3000/uploads/document/production_file/1/leader_pg_600.jpg
  </code></pre>
  
  <p>does show the file, and is identical to</p>
  
  <pre><code>&lt;%= @document.production_file_url %&gt;
  </code></pre>
  
  <p>why is this routing apparently not being seen?</p>
  
  <p>ImageMagick is installed and the application is running a resizing manipulation.</p>