00 00 00 12	- standard pix header
00 00 00 08
00 00 00 02
00 00 00 02

repeat the sections below for each image in the pix file

00 00 00 03	- C1 pix header
00 00 00 xx	- size of block. 11 + len(filename) + 1
03		- type: 8bit pix
xx xx		- rowsize, see note #1
xx xx		- width
xx xx		- height
xx xx		- halfwidth (for odd widths use: (oddwidth-1)/2)
xx xx		- halfheight (for odd heights use: (oddheight-1)/2)
??		- filename
00		- single 00 byte to signify end of filename

00 00 00 21	- C1 pix data
xx xx xx xx	- size of block. 8 + (rowsize*height)
xx xx xx xx	- number of pixels (width*height)
00 00 00 01	- pixelsize (1 byte for standard 8bit pix)

image data goes	- 1 byte per pixel, index of colour in C1 palette, see note #2

00 00 00 00	- end of pix block
00 00 00 00

========================================================

notes:

#1 rowsize

if both width and halfwidth are even then:
rowsize = width * pixelsize

if halfwidth is even then:
rowsize = ((halfwidth + 2) * 2)  * pixelsize

if halfwidth is odd then:
rowsize = ((halfwidth + 1) * 2)  * pixelsize

examples.
pix with a type of 3 always have a pixelsize of 1.

width		47
halfwidth	23
pixelsize	1
rowsize		48 = ((halfwidth + 1) * 2) * pixelsize

width		34
halfwidth	17
pixelsize	1
rowsize		36 = ((halfwidth + 1) * 2) * pixelsize

width		85
halfwidth	42
pixelsize	1
rowsize 	88 = ((halfwidth + 2) * 2) * pixelsize

width		64
halfwidth	32
pixelsize	1
rowsize		64 = width * pixelsize

#2 image data.

if rowsize > width then write the width followed by (rowsize-width) 00 records

example:

width		9
rowsize 	10
first row	A1 A2 A3 A4 A5 A6 A7 A8 A9
written as	A1 A2 A3 A4 A5 A6 A7 A8 A9 00