Is it possible to see the actual bytes of
card.raw from pset5?
If you are trying to see the actual bytes in the card.raw, perhaps so you can figure out if your "check for jpg start" is working, you can use xxd just as you did in pset5 with the bmp files.
As an example:
xxd -l 2400 card.raw
will give you a hex dump of the first 2400 bytes of the file.
Hope that helps, Brenda.