o	buffer
O	signed_buffer
M	buffer_size
X	index (global)
K	width
N	height
a	c
n	x
A	y
x	i
f	input
p	argc
q	argv
i	IF
w	t
W	cond
v	f
j	INPUT_BYTE
p	index (arg)
q	expected
J	GetChar
P	CompareHeader
Q	GetImageSize