title: listing other than windows images from amazon using fog
body: <p>I have been using fog for one of my project,i have used describe_images with filter parameters, but now i am getting only the windows images, so is there any way to get the other AMIs with changing the parameter(platform)?. lets an example <strong>'platform => linux'</strong> something like that</p>
  
  <pre><code>spec_images = @conn.describe_images('Owner' =&gt; 'amazon','platform' =&gt; 'windows')
  my_images = spec_images.body["imagesSet"]
  
  #  List image ID, architecture and location
  for key in 0...my_images.length
    print my_images[key]["imageId"], "\t" , my_images[key]["architecture"] , "\t\t" ,     
  my_images[key]["imageLocation"],  "\n";
  end 
  </code></pre>