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Images for Web Pages
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Graphical images enliven web pages, but must be used with skill
and caution to avoid various problems. This page illustrates
different kinds of images and how to use them effectively.
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you burden your web page's download time with big
graphics, consider other techniques for adding visual interest -
e.g. colored table cells, or colored
underscores (see below), or
style sheets.
Buttons and Icons
Buttons and Icons provide a simple way to
spice up web pages. In most cases they can be small in byte size and so
download relatively quickly - but be aware that every image causes an
additional trip to the server and so lots of icons can weigh your page
down even more than the corresponding number of bytes in a single
image. If your purpose is to provide image-based navigation then
consider using
image maps.
Backgrounds can enliven a web page.
Take care that they are not too large, and that they don't diminish
your page's readability.
Extremely small but still interesting backgrounds can be made by clever
use of patterns; this
(6x6 but shown here as 30x30) makes the background on
this page.
Rules
Horizontal rules can be used to segment a page.
However, they're frequently overused and may often be considered a sign
of amateurism. Consider the alternatives, e.g.
- use <HR>
- split the page into separate pages;
- Use colored underscores:
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The original GIF format was designed by
CompuServe in 1987,
so images in this format are of the type GIF87.
When the GIF format was extended in 1989,
CompuServe added several new capabilities to the GIF format including
transparency,
and streaming animation using multiple images in one GIF89a file.
GIF89a animation is a simple and cheap way to create
"instant animation".
It will allow a limited form of sprite-based animation.
You can add a smaller image to a larger one and change its co-ordinates
in following images.
You could for example, make a bird fly or a ball bounce.
Since the animation is done on the client side,
animated GIF89a images can be cached by the browser,
resulting in much faster frame rates.
When someone not using a browser that can handle GIF animation,
views your animation,
they generally see the first of your series of images,
not a broken icon.
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