[1.3.x] Fixed a security issue in image uploading. Disclosure and release forthcoming.

        file = open(file_or_path, 'rb')

        close = True

    try:

        # Most of the time PIL only needs a small chunk to parse the image and

        # get the dimensions, but with some TIFF files PIL needs to parse the

        # whole file.

        chunk_size = 1024

        while 1:

            data = file.read(1024)

            data = file.read(chunk_size)

            if not data:

                break

            p.feed(data)

            if p.image:

                return p.image.size

            chunk_size = chunk_size*2

        return None

    finally:

        if close: