Adobe PHOTOSHOP 5.0 User Manual page 331

GIF
The Graphics Interchange Format (GIF) is the file
format commonly used to display indexed-color
graphics and images in hypertext markup
language (HTML) documents over the World
Wide Web and other online services. GIF is a
LZW-compressed format designed to minimize
file size and electronic transfer time. The GIF
format does not support alpha channels.
You can convert files to GIF format using one of
the following methods:
The File > Save As command lets you save a
•
Bitmap-mode, grayscale, or indexed-color image
in GIF format and specify an interlaced display. An
interlaced image appears gradually in increasing
detail as it is downloaded from the Web but can
increase the file size. You cannot save alpha
channels with the image.
The GIF89a Export command lets you convert
•
an RGB or indexed-color image to GIF89a format,
specify interlacing, and define background trans-
parency. (See "Exporting images" on page 317.)
The GIF89a format supports single alpha
channels.
IFF
The Amiga Interchange File Format (IFF) is used
™
for working with Video Toaster and transferring
files to and from the Commodore Amiga system.
In addition, this format is supported by a number
of paint programs on IBM
computers. IFF is the best export format to use
with DeluxePaint from Electronic Arts. The IFF
format supports RGB, indexed-color, grayscale,
and Bitmap color modes, and does not support
alpha channels.
JPEG
The Joint Photographic Experts Group (JPEG)
format is commonly used to display photographs
and other continuous-tone images in hypertext
markup language (HTML) documents over the
World Wide Web and other online services. The
JPEG format supports CMYK, RGB, and grayscale
color modes, and does not support alpha
channels. Unlike the GIF format, JPEG retains all
color information in an RGB image but
compresses file size by selectively discarding data.
A JPEG image is automatically decompressed
when opened. A higher level of compression
results in lower image quality, and a lower level
of compression results in better image quality. In
most cases, the Maximum quality option produces
a result indistinguishable from the original. (See
"Saving files in JPEG format" on page 317.)
ADOBE PHOTOSHOP 5.0 323
User Guide
-compatible
®