ImageManip.setResizeThumbnail,In this method, the color is filled, only black
image = self.pipeline.createImageManip()
image.setHorizontalFlip(True)
image.setResizeThumbnail(480,640,0,0,255)
image_xout = self.pipeline.createXLinkOut()
image_xout.setStreamName("image_out")
image.out.link(image_xout.input)
cam.preview.link(image.inputImage)