Color Profiles for Website Images
This article is mostly for the benefit of graphic designers, who work in color-managed applications such as Adobe Photoshop or Illustrator, on properly calibrated monitors. This issue comes up often, usually when we're trying to explain why the colors on a finished web page look different than the colors in the original PDF mockup or the jpg images from the designer.
When you are creating images for website display, use the sRGB color profile. The reason is that sRGB is the closest profile to the way monitors display colors by default. Remember, you're working in a color-managed environment, but most users do not. This is usually why the colors on your designs don't look the same when viewed through a browser on a non-color managed system.
The only browsers that are color managed on Windows currently are Safari and Firefox 3. None of the others, including MS Internet Explorer (which is still the most commonly used browser and therefore the baseline to develop to, unfortunately), are color managed. So if you're working in Adobe RGB or ProPhoto RGB etc., the colors will look different to users than what you see on your own monitor when you're working. Other color profiles have a wider gamut than sRGB, so the colors can't display the same as you see them in PhotoShop or illustrator on your monitor.
It's fine to work with whatever profiles you want, but when you're working on files intended for web output, you should also work in sRGB so you can see what most users will see, and you should save your final output copies in sRGB. PhotoShop includes a "Save for Web" option that uses no profile at all.
When Microsoft Internet Explorer includes color management, of course, none of this will matter, and we can move on with our lives.
– by Don Ecsedy, Circuit Riders, LLC