Unfortunately, for lack of a bit of knowledge, many webmasters, uninitiated and some of relatively experienced, are using images in such a way as to disadvantage themselves and their websites. The most common problem I see is images that are way to big (and I don't mean physical size), which only serves to slow their website's loading time. I've noticed there are a number of webmasters who either aren't aware of fact that a website is no place for a bitmap image (.bmp) or they don't know how to convert it to a more friendly file.

Firstly, we have to establish major file types (or file 'extensions') that are used on websites. These are, as I just mentioned, bitmap (.bmp), which is a MS Windows® format, jpeg (.jpg), gif (.gif) and to a lesser degree png (.png). These initials all have meanings, for instance 'png' stands for 'Portable Network Graphics' but it's really of no consequence to name them all.

As I said, except in a very few circumstances, bitmap images have no place on a website, simply because of size of file needed to carry them. They certainly have their uses but this isn't generally a recommended use because they can slow loading speed (the time it takes for a web page to appear on a user's screen) to a virtual crawl, unless they are a very small or 'simple' image in terms of color and content.

What is a 404 page?

404 is a Hypertext Transfer Protocol status code. Hypertext Transfer Protocol is protocol web servers use to communicate with web browsers. When you type in a URL to try to visit a web page, your computer sends a request message to server and server sends back HTTP header to your browser, which includes a status message before you even see web page. Normally, if everything is correct, status code is “200 OK”, but you don’t see it because you see page you were looking for. But if server cannot find page you are looking for, it reports status as “404 Not Found”.

But what does it really mean?

The numbers 4-0-4 each actually mean something as individual digits. The first 4 is telling you, client, that there is a mistake on your end, such as a possibly mistyped URL or a request for a page that no longer exists. The 0 just represents a syntax error- it basically just means “something isn’t right”. Now after 4-0, last number could be any one of several digits that indicates type of error. The 4 in that section means that page cannot be located. Another status messages could be 401, which means you are unauthorized to view that page.

There is a clever myth behind 404 Not Found message. The story goes that 404 was room number of room where very first web servers were located. But there story includes a mystery- there is no room 404 in that building at CERN, where first web servers were held. So 404 Not Found code is a bit of an inside joke for those who have heard story.

How To Utilize Status Code Information

You can use your log files to spot “404s” by reviewing logs of your status codes. Take note any of 404 occurrences. If there seem to be quite a few, more than you could chalk up to user error, you might have a broken link in there somewhere. Check referring page, page user was at just before arriving that 404, then inspect that page to find broken link and fix it. If you do not have access to your log files, you can request them from your website host.

So why exactly do these 404 error pages exist?

The 404 Not Found Page comes up on your screen for several different reasons.

1) The page may have been moved. In this case, it is as though you are trying to visit a friend when you find a note taped to their door that says they have moved. But it doesn’t tell you where they moved to. Not very helpful, is it? The 404 Not Found page is a note like that.

2) The hyperlink you followed my have a minor error in URL.

3) The page may simply be gone. Not moved. Just taken down. And whatever linked you to it doesn’t know it. This is a form of Linkrot.

Linkrot refers to outdated or abandoned URLs across Internet. If you take a page down or change URL, other sites that have links to your page will have wrong URL, causing Linkrot to occur, and sending people who click on those links, expecting to come to your page, right for a lovely visit from Error Page Fairy.

How do you avoid Error Page? Help stop Linkrot. If links continue to lead to dead ends, flow of Internet will be interrupted, dramatically reducing usability of web. You may not be able to stop another site from screwing up URLs linking to your site and creating a dead link to your site, but you can at least maintain links and pages on your own site.

You must regularly check outgoing links from your site to make certain that they still lead to existing pages. It is your responsibility to ensure that links on your site lead to actual destinations and not error pages. Internal links should be maintained as well. AlertBox’s Jakob Nielsen believes that URLs should “live forever”; that there is no reason to let a page you built languish abandoned and outdated.

Of course, sometimes you cannot help but remove a page or change its URL, and you will not be able to always prevent occurrence of an Error Page. But if you can’t avoid an Error Page, at least make it work for you!

Good Error Page: Not An Oxymoron

Turn an error into an advantage by designing your own error page for your site and making it interesting, informative, helpful, and even fun.

According to Jakob Nielsen there are 5 rules for making a good Error Page:

1) Design an error page specific to your site, rather than sending your visitors to browser’s standard Error page.