jQueryFileUpload在直接上传到S3时调整图像大小

I'm using the awesome jQueryFileUpload plugin. I'm now uploading directly to S3 simply by changing the server-side option upload_dir from my server to s3 like this:

    $this->options = array(
        'upload_dir' =>'s3://'.$this->bucket.'/'.$this->prefix,

See the uploadHandler.php for full code.

That is so easy I was shocked. But there is always a catch and the catch is that now you can't do generate thumbnail server-side.

I think the problem lies with handle_image_file() and the $file_path for image processing being the S3 url instead of the tmp directory where the file is uploaded to.

Can one process an image in the tmp directory? Or better yet, how can I access the s3 file to do the image processing on that?

Any Help?