the problem is, there are different header formats, and then depending on the BPPs, it affects the colour table size too. But then, without knowing how long each line is (information from the header), you wont be able to work out how much padding each line has (as in the data section, if a line is not divisible by 4 bytes, it is padded).
So, the only way you are able to skip the header, is if you know you always have the same image size, and same header format.
Even simpler - get a microprocessor to convert it to raw data for you.