|# of colors||Percentage|
|16 or less||0.01%|
|Thousands (16 bit)||10.87%|
|Millions (24 bit)||8.29%|
|Millions (32 bit)||80.51%|
Similar figures from a broader range of sources can be found on Chuck Upsdell's Browser News website.
As you can see, the vast majority of users can see full true-color images with no "dithering" or other ill effects. In the early years of the web, many users still had 256-color displays, and web browsers used a standard palette of colors, using patterns of those colors to reproduce additional colors. As a result, older books and websites may advise you to design for the "safe web colors," but this has not been necessary for several years. The 0.32% who are still at 256 colors are usually Windows users temporarily running Windows in "safe mode," or in some cases users of handheld devices. In both cases their expectations of graphical quality are not high.
Be aware that users with graphics cards that display "millions of colors" may still see low-quality versions of your images if they are using America Online or another service that severely compresses your images to speed up slow dialup connections. Usually, there is a way for these users to fetch a full-quality version of your image. If you know that your site is especially popular with AOL users and these customers are very important to you, you may wish to consider designing images with a smaller number of solid colors rather than many gradient fills and other effects that AOL's compression does not reproduce well, but this will limit the quality of your site for other users who are not suffering with dialup connections. For more information, see why do images look bad on my computer? and why do images keep saving in ART format?
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