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)
(C code but still pretty useful)
PCX is of course (tm) Z-Soft Corp.
Copyright 1995 Kevin M. Luck