Graphics Reference
In-Depth Information
.png
The .png format was specifically created to replace the .gif format.
Although the file size of a .png graphic may generally be larger than
that of a .gif, remember that .pngs support true-color imaging. Like
.gifs, .png files use lossless data compression and support transpar-
ency.Unlike.gifs,.pngsdon
t include a pixel border around the
nontransparent area of your images. Because of the true-color ima-
ging and better alpha transparency, .pngs are ideal when you have
photographic-style images that need to animate across a multicolor
or gradient background. Figure 5.7 illustrates the same image from
Figs. 5.5 and 5.6 on the same background. However, Fig. 5.7(a) is a
.gif and Fig. 5.7(b) is a .png. Note the lack of a white border around
the nontransparent areas of the .png.
'
TIP
Both .gif and .png formats support transparency. However, .gif files will
give you a border that appears as an outline around the opaque area of
the image. In addition to the absence of the pixel border, .png files
usually have a better image quality than .gif files. The cost of that better
image quality is, of course, file size.
TIP
When you
'
'
re working with .pngs and you
re saving your files through
Photoshop
ll usually want to go with
png-24. However, if the color palette contains fewer colors, then you may
want to use png-8.
'
s
Save for Web
&
Devices,
you
'
Figure 5.7 A .gif (a) and a .png
(b) on the same gradient
background.
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