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 tones.
JPEG (Joint Photographic Experts Group) file format is the superior format
for photographic or continuous-tone images, because JPEG files can contain
millions of colors. As the quality of a JPEG file increases, so does the
file size and the file download time. You can often strike a good balance
between the quality of the image and the file size by compressing a JPEG
file.
PNG (Portable Network Group) file format is a patent-free replacement for
GIFs that includes support for indexed-color, grayscale, and true-color
images, and alpha channel support for transparency. PNG is the native file
format of Macromedia Fireworks MX. PNG files retain all the original layer,
vector, color, and effects information (such as drop shadows), and all
elements are fully editable at all times. Files must have the .png file
extension to be recognized as PNG files by Macromedia Dreamweaver MX.
JPEG (Joint Photographic Experts Group) file format is the superior format
for photographic or continuous-tone images, because JPEG files can contain
millions of colors. As the quality of a JPEG file increases, so does the
file size and the file download time. You can often strike a good balance
between the quality of the image and the file size by compressing a JPEG
file.
