Image file format

You should normally not need to know the image file format, and you should not depend on it being constant.

All offsets are from the start of the file.
All blocks should start at a word-aligned offset, though versions of StrongHelp before 2.53 didn't do that correctly.
The block size includes the two leading words, but is not neccessarily aligned. The offset from one block to the next should be (blocksize+3) AND NOT 3 (if version >= 2.53)
Well, that's not strictly true.. Between the blocks there can be a sequence of zero bytes. (When a FREE block is reused, whatever is left over is made into a new FREE block, but only if it is > 32 bytes. Else it is just zeroed out.)

File header

+0	"HELP"
+4	Size of root block (Versions pre 2.60 said 40, although correct size has always been 44..)
+8	Version of StrongHelp that created this manual.
+12	Offset to first free block. -1 if none.

	This simulates a directory entry above* the root dir*

+16	Offset to root dir
+20	load address
+24	exec address
+28	size (excluding the two first words)
+32	flags
+36	Reserved
+40	"$"

Directory block

+0	"DIR$"
+4	Size of block
+8	Used

	Then comes zero or more of these

+0	Offset to object
+4	Load address
+8	Exec address
+12	Length of object (not counting guard and length word)
+16	Flags
	0	owner read
	1	owner write
	3	locked
	4	public read
	5	public write
	8	is directory
+20	Reserved
+24	Name. Zero terminated and padded with zeros to word limit.

Data (file) block

Free block