title: Different image output when saving as
body: <p>I want to be able to generate a different image (with watermark) when the user save the image.</p>
  
  <p>I know that :</p>
  
  <ul>
  <li>Broswer send text/html when it's direct image access and image/jpeg (image content-type) when it's included in a src=""</li>
  </ul>
  
  <p>So if the browser query the server from a src="", it send the good content-type. If the broswer go on the image url it does send text/html,application/html+xml, etc...</p>
  
  <p>Anyone know how to make the watermark happen if the user do the command "Save as" ?</p>
  
  <p>Thanks</p>