title: Leverage browser caching - external images
body: <p>I've been able to correctly (I think) enable caching on IIS. The only problem now is that when I run Google's PageSpeed Insights it still says</p>
  
  <blockquote>
    <p>Setting an expiry date or a maximum age in the HTTP headers for static resources instructs the browser to load previously downloaded resources from local disk rather than over the network.</p>
  </blockquote>
  
  <p>But all of the suggestions are external images. I am using Amazon's S3 to externally host images (linking to direct URLs, as </p>
  
  <blockquote>
    <p>&lt; img src="http://s3.amazon.com......."/>. </p>
  </blockquote>
  
  <p>Is there a way I can "leverage browser caching" for these external images?</p>
  
  <p>Thanks in advance.</p>
  
  <p>Andy</p>