Comment 4 for bug 874871

Yeah, ristretto displays color images. But with the wrong colors depending on the screen.
See http://en.wikipedia.org/wiki/Color_management

And try to display this in Ristretto: http://img.fotocommunity.com/photos/4763821.jpg
(Gelb should be yellow, Grün should be green, Blau should be blue, Purpur should be purple and Rot should be red)
Ristretto is incapable of displaying this image correctly as It does not know about color management (this is an extreme test image to show whether a program understands CM or not)

Displaying images without color management leads to unpredictable colors because no two screens display the same binary values in an image file identical.
As long as sRGB screens where the common ground that was ugly but not much of a problem for the masses. Now that wide gamut screens that display a gamut of Adobe RGB or wider become more and more common this problem will affect more and more people as the common assumption of everything is sRGB just does not work anymore.

As ristretto is the default image viewer that everyone who installs XFCE will get it should either handle images properly or be exchanged for a program that does it.