I've found a couple of problems with the gimp using 16 bit gray images
the first is that it can't open 16 bit gray pnms the second is more of
problem in that saving as png silently converts them to 8 bit gray pngs.
This is with gimp-1.3.8 I couldn't spot any mention of this in bugzilla
but I'm not really any good with it so I could have missed something.
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