title: imgkit get height of image
body: <p>what I'd like to do is very simple. I have a code which uses a imgkit library to load some webpage image and then stores it. It looks like that:</p>
  
  <pre><code>kit = IMGKit.new(site, :quality =&gt; 5, :width =&gt; 1024)
  img = kit.to_img(:png)
  file = kit.to_file("#{Rails.root}/public/images/#{s2}.png")
  </code></pre>
  
  <p>I need to know the image height after loading in order to stretch canvas element behind it. Is there a way I can get the height ? Or if not, how could I achieve this without knowing the image height before loading, javascript ?</p>