Many different types of graphic file formats
exist, but three graphic file formats are generally used in web
pages—GIF, JPEG, and PNG. Currently, GIF and JPEG file formats
are the best supported and can be viewed by most browsers.
PNG files are best suited for almost any type of web graphic due
to their flexibility and small file size; however, the display
of PNG images is only partially supported in Microsoft Internet
Explorer (4.0 and later browsers) and Netscape Navigator (4.04
and later browsers). So unless you are designing for a specific
target audience using a browser that supports the PNG format,
use GIFs or JPEGs for broader appeal.
GIF (Graphic Interchange Format) files use a maximum of 256
colors, and are best for displaying noncontinuous-tone images or
those with large areas of flat colors, such as navigation bars,
buttons, icons, logos, or other images with uniform colors and