The INFO "About to return NULL from unhandled branch" appears when creating a PDJpeg from a stream. Although the message is an INFO and not a WARNING or an ERROR, it scares users.
The message happens because getRGBImage() calls getColorSpace() although the colorspace isn't known yet, it is determined after the call to getRGBImage(), which loads the image.
The image objects were completely redesigned in 2.0, so it makes no sense to waste time for a real solution to this. I am setting the message to DEBUG instead, and make it less scary.