title: attachment_fu image resizing with s3 storage
body: <p>I'm facing a problem right now, where in my company, we want to resize the thumbnail images we have on amazon s3 storage using attachment_fu, I've been investigating how to regenerate this thumbnails and had found some guidelines to do it, however all of them work with local storage. </p>
  
  <p>I've found a way, that involves more or less downloading the image from S3 using RestClient, and then assigning each downloaded image to each photo instance as a new attachment, I don't know if this is the best way (slow, expensive?), I would like to know if someone out there have had the same situation, did you do more or less the same? or did you find a more elegant way to solve this issue?</p>
  
  <p>Thanks in advance for any feedback.</p>