As a follow-up to my last exploration, Using the BeforeUpload event to generate per-file Amazon S3 upload policies, I wanted to see if I could also generate a client-side preview of the selected images. Now, I've tried working with Plupload previews before, but never in the context of saving the record before the upload (as I did in my previous exploration). As such, I wanted to look at how to best combine the power of the per-file Amazon S3 upload policy with the perceived performance boost of a client-side preview.