[Coco] Sockmaster HiColor and Rascan IMG file format

[Joel Ewy]

I've had a lot of fun playing with Sockmaster's HiColor program, using
BMP files I've scaled down and converted from JPEGs using NETPBM.  But
the program can ostensibly display significantly more than 256 colors. 
I'd like to see if I can tell the difference between a 12-bit source
image and an 8-bit source image.  Problem is I don't have any good .IMG
files to test it out with.  Ideally, I'd like to be able to convert
JPEGs into 4096 color .IMG files myself.

Anybody know if there is any utility aside from the RASCAN software that
can create .IMG files?  Failing that, is the file format documented
anywhere so I could roll my own?  I would likely be able to modify
ppmtotga into ppmtoimg4k or something like that. 

If none of the above are available, does anybody know of any repository
of good 4096 color IMG files?  Oh, for the days of Delphi...

Of course, it would also be cool if HiColor could read in some other
file formats.  Hey Sock, any chance you'd let the source code out of the
bag?  :)

JCE