I need to do a little file manipulation with VBA

I am pulling blob data out of ms sql server using text copy, the files
are jpeg files that have had tags added to the front of the file, and
of course could be fairly big.

I know that the actual jpeg begins with a particular 4 characters, so I
could identify how many characters into the file i have the real file
starting.

Now if this was a string, I would just use instr to find the start and
right(x$,len(x$)-instr(1,x$,instr$)) to get the data. But this is too
damn big for that method.

Any suggestions? Do I have to do this character by character? if so I
could use a little help with how.