Here's some code for SWAG to dump the current mode $13 screen
to a PCX file.
Feel free to use/modify, just give credit.

Also, if you do a good mod of it (ie, A mode X version,
faster compression, whatever), I'd love to see it.

Reference: Bit-Mapped Graphics (2nd Edition)
    Steve Rimmer
    ISBN 0-8306-4209-9
    (C code but still pretty useful)

PCX is of course (tm) Z-Soft Corp.

Copyright 1995 Kevin M. Luck