title: Caching an image to return code 304 rahter than 200
body: <p>I have some images in my website that rarely change, but the page reload rerenders them over and over again, returning code 200 OK. I would like to cache those images so I'll get back a 304. 
  I'm using the Spting MVC, and I have used the HttpServletResponse setHeader method. </p>
  
  <pre><code>    httpResponse.setHeader("Cache-Control", "max-age=36000"); 
  </code></pre>
  
  <p>Problem is that this method sets the header to the entire response, rather than to a single image. What I would like to do is set the headers to a single file being transfered in the network, such as image. How can I achieve that? </p>