title: Setting expiration of files in SharePoint in a document library
body: <p>I got a SharePoint-Site that has images in a special asset-sitecollection. These images have a max-age of "0" by SharePoint default, so won't be cached. </p>
  
  <pre><code>Cache-Control:private,max-age=0
  Date:Fri, 23 Nov 2012 10:44:56 GMT
  ETag:"{C7D03C94-3DC1-49BB-86DA-EFC71BC61058},1"
  Expires:Thu, 08 Nov 2012 10:44:56 GMT
  Last-Modified:Wed, 07 Nov 2012 17:00:50 GMT
  </code></pre>
  
  <p>I want to change that behaviour. It would be Ok if not only the files in the documents site collection is cached but anywhere, because this site collection does not contain any other files.</p>