Synchronous resize and upload using graphicsmagick

I am trying to make resizing of a photo and uploading to a server synchronous. I believe the key will be making the stream function synchronous.

function upload(photo, newname, size, cb) {
  gm(request(photo))
  .resize(size[0], size[1])
  .stream(function(err, stdout, stderr) {
      var buf = new Buffer('');
      stdout.on('data', function(data) {
          buf = Buffer.concat([buf, data]);
      });
      stdout.on('end', function(data) {
        var data = {
            Bucket: config.s3_bucket_photos,
            Key: newname,
            Body: buf,
            ACL: 'public-read', 
            ContentType: "image/jpeg"
        };
        uploadToServerSynchronous(data, cb);
      });
    });
}

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