The latest Firefox 3 alpha has added support for color management, a standard technique defined by the International Color Consortium to ensure consistent color presentation for images no matter they are displayed on paper, a CRT screen, an LCD, fabric, etc.
The ICC offers an ICC2 and ICC4 standards compatibility test and I ran it with Firefox 2 (to the left) and Firefox 3 Alpha 7. You can see the results below.
While image color improvement will not be as dramatic as these test image could suggest there will certainly be an difference. For example, when you take a picture with your digital camera (specially in RAW format), it not only saves information about the colors but also the amount of light available, distance and other factors that may affect how an image is perceived. This details are stored in a color profile which as of Firefox 2 is just ignored.
In Firefox 3 Alpha 7, these profiles are used to tune the image to your display to better reproduce the original scene, a must for amateur and professional photographers, clothing and fabric related e-stores, paint, food, and mostly everywhere a true representation of color is important.
Color management is turned off by default to prevent subtle color variations affecting the overall look of web sites. To enable it you must set gfx.color_management.enabled to true (via about:config) and restart Firefox.