Image maps rendered w/o assumed_gamma in the global_settings look
acceptable. But if you put "assumed_gamma 1" there (as you should,
actually), you're applying Display_Gamma (2.2 by default) which makes image
maps way too bright. Since such output conversion to Display_Gamma is
apparently the right thing to do, the question is what to do with the
images.

The only solution I've been able to discover so far is to load the image
into Photoshop, select "Image --> Mode --> Assign Profile..." and assign a
prifile (a "Generic 2.2" or the so-called "Working RGB", which seems to be
of gamma 2.1 but has the advantage of sparing you conversion questions the
next time you try to load saved image). Then save the image in PNG format
and use that image in the "pigment { image_map { png "my_image.png" }}";
POV-Ray (its libpng) seems to be able to understand stored profile
perfectly. BTW, converting image *pixels* (from current gamma of 2.2 to
gamma 1, so that the implicit inverse conversion by POV-Ray would restore
textures' original outlook) was not even considered, for obvious reasons.

So far so good. But the disadvantages are numerous... First of all, you
cannot use any format except PNG, which would be [almost] OK -- if there
were no need to use JPEG, at times. Although Photoshop seems to be able to
store profiles within jpegs as well, POV-Ray currently cannot pick them up.
Second, if you edit the PNG file with [almost] any program except Photoshop,
kiss your gamma profile goodby.

So, gentlemen, are there any suggestions? As to me, the only feasible
solution I can think of is to add support for "gamma <value>" to the
image_map statement. Relatively simple, and yet should work perfectly.

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