title: Rails Image Tag Helper
body: <p>Using Rails, I'm fine with the image tag helper in an HTML file but how do I include images in a CSS file. I've tried replacing the url from:</p>
  
  <pre><code>background:url('/assets/img/banners/img3.jpg')
  </code></pre>
  
  <p>to...</p>
  
  <pre><code>background:url(&lt;%= image_tag "banners/img3.jpg" %&gt;)
  </code></pre>
  
  <p>but this doesn't work. Do I need to change the extension of my css files to make it work?</p>