umans tend to be visual creatures?and the Web reflects who we are.

Back when it started, the Internet was a text-only medium. Hard to imagine now, isn’t it? A bit like imaging TV with captions but no pictures or sounds!

Things were simpler back then, bandwidth requirements far less demanding by necessity, since bandwidth itself was so severely limited. It was an imageless, text-centric world.

Passionately visual creatures that we are, this situation soon changed…and changed with a vengeance! Along came the Web and and the Web browser and suddenly the online world was teeming with graphics.

Some of these graphics are useful and functional…while others are empty, bandwidth-hogging, and sometimes just plain annoying. With just a little knowledge and planning, you can make sure all your graphics fall into the first category and are additions that make your site a better place to visit.

Graphics are about more than adding a “pretty picture” to a Web page.

You’ll find graphics incorporated in more ways than you might at first realize:

• Many are right out in the foreground, in the form of splash images, photographs, and logos.
• Others are part of a navigation system, used as image maps and icons.
• Others are a bit more difficult to spot and appear as background images, watermarks, graphic bullets and lines, graphic text, and invisible “spacer” graphics that are used to fine-tune page layout spacing.

Graphics in Use

Here’s some different types of graphics, each with its own purpose.

The Bandwidth Bottleneck

You’ve heard it before and you’ll hear it (many times) again throughout the width and breadth of this site that all-important word: bandwidth.

Bandwidth refers to how fast data can be transferred across the network. It is the greatest limiting factor as you add graphics to your site. This is not an issue with text files because those files are usually small and text data takes up very little room. But with graphics it is a whole other story!

Graphics files?and graphics data?fill much more file space than text files and to understand how your readers will see your page, you’ll need to be aware of bandwidth issues.

A Picture Is Worth…
Think of it this way. If one picture is worth a thousand words, thats a text file.

Another way to think about image file size is by download time. How long would you wait for an entire Web page to download? Twenty seconds? A minute? Longer? (I doubt it…) Heed the Golden Rule of Web-page creation:

Do not ask your users to wait any longer than you would happily wait for an entire page to download.

Bandwidth Guidelines

Try these simple rule-of-thumbs tests for gauging file size.

Connection speeds vary and Internet traffic comes and goes…so how can you know how long your page will take to download? Well, you can’t, not exactly anyway. But here’s a good, conservative rule of thumb: Count on your “average” user needing about one second to download each 1K of data.

Practically, this means that:

• A 30K image will take about 30 seconds to download.
• A web page containing a 30K image and six 10K icons, and a 10K html file, and a 20K background image will take two full minutes to load.
• Add a few more 30K images, maybe a picture or two of your dog and some fancy graphical text, and suddenly you’re looking at four very long mimutes.

You’d better have a loyal group of unusually patient readers, because normal, red-blooded, type-A surfers will stick around for maybe 10 or 15 seconds before blithely jumping away to some place else.

Set yourself a maximum size for each Web page again, this includes everything on the page and stick to it!