CHAPTER 12
212
Optimizing Images for the Web and E-mail
4
Select Progressive to create an image that
displays progressively in a Web browser.
Progressive images display first at a low resolution,
and then at progressively higher resolutions as the
image downloads. If you chose Optimized to
create a smaller file, the Progressive option won’t
be available.
Note:
Progressive JPEGs are not supported by some
browsers.
5
To preserve the ICC profile of the original image
with the optimized file, select ICC Profile.
ICC profiles are used by some browsers for color
correction. The ICC profile of the image depends
on your current color setting. (See “About color
management” on page 31.)
6
If the original image contains transparency,
select a Matte color that matches the background
of your Web page. Transparent areas in your
original image are filled with the Matte color. (See
“Making transparent and matted images” on
page 214.)
7
To save your optimized image, click OK. In the
Save Optimized As dialog box, type a filename,
and click Save.
Setting optimization options for GIF and
PNG-8 formats
GIF is the standard format for compressing images
with large areas of solid colors and crisp details like
those in line art, logos, or type. (See “About GIF
format” on page 209.) Like the GIF format, PNG-8
supports transparency, and efficiently compresses
areas of solid color while preserving sharp detail;
however, not all Web browsers can display PNG-8
files. (See “About PNG-8 format” on page 209.)
Optimization options for GIF format:
A.
Optimization format
B.
Color reduction
algorithm
C.
Dither algorithm
GIF format and PNG-8 format can use up to 256
colors to describe an image. The process of deter-
mining which colors to use is called indexing, so
images in GIF and PNG-8 formats are sometimes
called indexed color images. To convert an image to
indexed color, Photoshop Elements builds a color
lookup table, which stores and indexes the colors
in the image. If a color in the original image does
not appear in the color lookup table, the appli-
cation either chooses the closest color in the table
or simulates the color using a combination of
available colors.
To optimize an image in GIF or PNG-8 format:
1
Choose GIF or PNG-8 for the optimization
format.
2
Select Interlaced to create an image that displays
at low-resolution in a browser while the full-
resolution image is downloading. Interlacing can
make downloading time seem shorter and assures
viewers that downloading is in progress.
A
B
C
