This will be a painful bug to fix; so painful that most people won't even
want to think about it.  If you're the type to stick your head in the sand,
then discontinue reading now.

The display of most of our computers is wrong.  Light emitted isn't
proportional to signal strength.  We set our highs and lows on the monitor,
but the values in between are not linear, but a ugly U-shaped curve; on our
PC-ish hardware, images are much darker than the data in the file is.  

When we build our images and icons atop the foundation of this dark curve,
we shim up the brightness so that it looks correct to us on our monitor. 
When we see an image from outside our computer, like a digital camera,
which (correctly) doesn't fill in our bad gamma-curve, the images look dark
to us.  Black is still black, and white is still white, but the medium grey
that should be right in the middle, is much darker than it should be.

To make sure you understand the problem, consider this image:
  http://images.chad.org/paris/chad-place-de-vosges.jpeg
The image is too dark, but it is not under-exposed.  The problem is your
and my displays.  While viewing that image, open a new xterm and type
"xgamma -gamma 1.7" .  Pow!  

That image now looks like it should (or close to it).  But, unfortunately,
note that many of your other icons are washed out.  Thus, we arrive at the
crux of the matter.

There are two problems to be solved (which I suggest making as blocking
bugs to this ueber-bug):

*  GNOME should offer as a preference (defaulting to a sane value) setting
of the X server's gamma correction value.

*  Many GNOME applications' icons are too light -- they are designed to
look correct after looking through the broken lens of our displays.  (Some
use PNG which is (thankfully) designed to handle gamma correction
internally, but (terribly, horribly) is not implemented in some/most/all?
versions of libPNG so even though a number exists in the file, it's
(excruciatingly) the wrong value.  Not supporting gamma is bad, but seeming
to and getting it wrong is much worse.)

The first item/bug, I'm not sure where to file it.  control-panel?

The second item might mean filing minor bugs on projects that don't use PNG
or once used it incorrectly when creating their images.  An enterprising
individual (perhaps me) might create a script that converts images from the
default bad gamma values to good values and munge images in batch so
project managers can fix it themselves in one swoop.

We can't affect what the outside world will create for us, but we can fix
our own images and adapt to the correct gamma curve.

I sincerely think gamma correction is a problem is worth solving, and that
once understood (which is nontrivial) will seem worthy of solving by those
affected.


More URLs that describe the problem:
  http://www.cgsd.com/papers/gamma.web.html
  http://graphics.stanford.edu/gamma.html