What is a RAW bitmap? Basically it is a large continuous stream of bytes where each byte represents 8 monochrome pixels. That's it. There is no header at the front to tell the reading application anything about the stream of bytes.
In order to view a RAW bitmap the user has to, at a minimum, inform VLBV of the "width" of the bitmap.
In most cases, the bitmap should be byte aligned - i.e. the width (in pixels) should be a multiple of 8.