Image to to Stream of Byte[]?

Question

I have an image in the pictureBox captured from a device.Now  i want to convert this PicBox.Image to stream of bytes to save it in the DataBase.Plz help me how to convert this image from pictureBox to stream of bytes.I pretty know how to save it in database but having some problem converting the image to stream of bytes from PictureBox.
Thnx in Advance!