How to Prepare Images for Your Web Site – Part 2

When surfing the Web, you will have noticed web sites where the
images load very slowly whereas other images don't match with
the theme of the site or appear blurry. Presenting a

professional
image for your business means your web site design must be
professional also.

Part one of this article discussed when to use images for your
web site and what image file formats to use on the Web
(www.isitebuild.com/imageoptimization1). In this article (Part

2),
we will discuss how to optimize your images for the Web.

Image optimization is the art of making your images suitable
for the Web. There is a large difference in preparing your
graphics for print compared to the Web. In print you have to
have as much data as possible to get a good graphic. The main
factors that influence the display of graphics for the Web, are
the size of the file and the screen display quality of the
graphic.

Factors Affecting Web Graphics

1. File Size
When you design web pages you need to create a balance
between visual appeal and page download time. If your
page has too many images on it, it will take too long too load
and visitors will not stay around to wait.

2. Cropping
This means cutting out unwanted areas of your image.
It decreases the file size and helps visitors to focus on your
image.

3. Anti-aliasing
Jagged edges of an image can be prevented by anti-aliasing.
This creates a blended edge around an image.
Because of the extra colors necessary to create the blend,

file
sizes of anti-aliased GIFs are a little larger. Use
anti-aliased graphics in almost all cases, except when

creating
very small type as graphics.

4. Bit Depth and Screen Resolution
Bit depth refers to the number of colors in an image or the
number of colors a computer system is capable of displaying.
To calculate bit depth, one bit equals 2 colors, then multiply
2 times 2 to arrive at each higher bit depth. Quality and file


size decrease as bit-depth decreases.

New computers support thousands or millions of colors (32-bit),
but many older color systems can only show up to 256 (8-bit)
colors at a time. This reality imposes limits on the size of
files and number of colors that can be included in Web
graphics.

Check how your image appears with a 256-color monitor and a
true-color monitor. Do this on your PC using the
Setting/Control Panel/Display option, then select the Settings
tab/256 color option.

3. Image Resolution
Monitors typically display data at 72 dpi (dots per inch).
Therefore, always save your files on the Web at 72 dpi.
Always resize your image in your graphics software
before you insert it onto your web page. If you resize its
dimensions when it's already on your site, it will look
distorted.

6. Browsers
Someone viewing your site is subject to a completely
different result depending on which browser he is using. Your
images may appear harmonious in Internet Explorer (IE) but may
be broken up in Netscape Navigator (NN). Therefore check your
image for differences with Internet Explorer (IE) and Netscape
Navigator (NN) browsers. Your images should appeal to all
users.

Unfortunately AOL has its own browser, which filters sites
through its own AOL proxy system. This means all graphics are
converted from JPEG and GIF to the ART format.

Most AOL users also use their browsers with the default
"compressed graphics" checked, so what normally looks good in
IE or NN, will look blurry or distorted on AOL. To change

this,
AOL users need to go to preferences and check "never compress
graphics".

7. Caching
This is a temporary storage area of your hard drive where
browsers keep files while they display them. You can
create a consistent look and feel to your Web Site, by reusing
another graphic on another page. You will be retrieving it

from
the cache. The more graphics that you reuse, the faster your
pages will load.

Testing
To test load times of your pages you need to first
publish them and then clear the cache in your computer before
loading them, and timing them, from the Internet. Put the url
in your browser address box, start timing when you hit Go and
stop when the word 'Done' appears in your status bar.

Images are the main factor that contributes to slow loading of
your web pages. By implementing these techniques for optimizing
your images, visitors will have a far more pleasing experience.

Part 3 of this article will discuss other methods for creating
fast loading images when creating a professional web site.