*** C64 (PC64 saved-session image)
*** Document revision 1.1

  These are files created when you save a C64 window under PC64 (DOS only).
It consists of a 64k memory dump, color ram dump, I/O ports,  the  name  of
the ROM images you were  using  at  the  time,  and  user-setable  options.
Typical size is around 69091 bytes.

       00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
       -----------------------------------------------
00000: 43 36 34 49 6D 61 67 65 00 .. .. .. .. .. .. ..   C64Image........
 ...
00000: .. .. .. .. .. .. .. .. .. 2F 37 00 AA B1 91 B3
00010: 22 22 00 00 4C 00 FF 00 04 00 00 00 00 00 00 19
00020: 16 00 0A 76 A3 00 00 00 00 00 00 76 A3 B3 BD 00
00030: 00 00 00 00 01 08 03 08 03 08 03 08 00 A0 00 00
 ...
10000: .. .. .. .. .. .. .. .. .. 0E 0E 0E 0E 0E 0E 0E
10010: 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E
10020: 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E
10030: 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E
 ...
10400: .. .. .. .. .. .. .. .. .. 0E 0E 0E 0E 06 06 06
10410: 06 00 00 00 00 00 00 00 00 00 00 C8 00 20 34 37
10420: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
10430: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
10440: 20 20 20 20 20 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E 0E
 ...

  Byte: $00000-00008: The signature "C64Image" followed by a $00. Note  the
                      varying case of the text.
         00009-10008: Main memory of the C64 (64K, $0000-FFFF)
         10009-10408: Color memory (1k, $D800-DBFF)
         10409-?????: I/O memory and user-selectable options (ROM  version,
                      etc). The ????? means the end  of  the  file  is  not
                      known, since these files can vary in length.

  Since these files are only supported by PC64 for DOS (*NOT*  for  Win95),
it is not worth getting too much into  the  layout.  I  was  attempting  to
decipher the layout of the I/O ports and options area but decided it wasn't
worth it.