title: Elegant way to create thumbnails of images stored on s3 with ec2 and communicate with rails on finish?
body: <p>OK, so a quick summary of my setup and what i want to accomplish:</p>
  
  <ol>
  <li><p>I have a rails 2.3.5 server that runs my website. I have a flash application on my site where users can upload images directly to s3. </p></li>
  <li><p>When an upload is completed, rails is notified. </p></li>
  <li><p>At the point where the image is finished uploading to s3 and rails is notified, i want rails to send some post to something located on ec2 to create two thumbnails (110x110 and 600x600).</p></li>
  <li><p>When the thumbnails are created and transferred to s3, i want whatever process on ec2 to send a post back to rails to notify that the thumbnail creation is finished and are on s3. </p></li>
  </ol>
  
  <p>What is the best way to accomplish this? I have looked at tools such as <a href="http://wiki.opscode.com/display/chef/Launch+Cloud+Instances+with+Knife">knife</a> very briefly but I'm not familiar at all with using ec2 or similar services.</p>
  
  <p>Thanks</p>