Q:

convert BufferedImage to JPG byte array

I'm working on a processing platform for images and my server is currently accepting images as byte arrays from the client using pythons PIL.Image methods. I'm also currently using Java as a front end to grab image frames from video with the FrameGrab utility and returning them as a BufferedImage object. What I don't understand is how I am meant to convert from this buffered image object to a jpg byte array and could use some help.'
I've found an example of writing out a 
Here is the base portion of my code.
            BufferedImage frame;

            for (int i = 1; i < 100; i++) { 
                try {
                    frame = AWTUtil.toBufferedImage(FrameGrab.getFrameAtSec(videoFile, i * .3));

                } catch (IOException ex) {
                    Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, ex);
                } catch (JCodecException ex) {
                    Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, ex);
                }
            }

My python server backend is currently just attempting to save the file with the aforementioned library like so:
        img = Image.open(io.BytesIO(data))
        img.save('test.jpg')

A:

The easy way:
public static byte[] toJpegBytes(BufferedImage image) throws IOException {
  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  ImageIO.write(image, "jpeg", baos);
  return baos.toByteArray();
}

If you want more control over the conversion (compression level, etc) see Setting jpg compression level with ImageIO in Java.

