Orphan: Alt Attribute & SEO Optimization

SEO Optimization images has become more and more essential in SEO (Search Engine Optimization) for websites. The ALT attribute is a critical step that is often overlooked. This can be a lost opportunity for better rankings.

In Google's webmaster guidelines, they advise the use of alternative text for that images in your site:

Images:. Make use of the alt attribute to provide descriptive text. Additionally, we recommend using a human-readable caption and descriptive text around the image.

Why would they ask us to achieve that? The answer is easy, really; search engines like google have a similar problem as blind users. They can't see the images.

Many webmasters and inexperienced or unethical SEOs abuse the use of this attribute, trying to stuff it with keywords, looking to achieve a certain keyword density, which isn't as relevant for rankings now as it was previously.

On the other hand, high keyword density can, on some search engines like google, trigger spam filters, which might result in a penalty for your site's ranking. Even without such a penalty, your site's rankings won't benefit from this tactic.
This process also puts persons who use screen readers at a greater disadvantage. Screen readers are software-based tools that actually read aloud the items in what's shown on the screen. In browsing the net, the alt attributes of images are read aloud too.

Imagine listening to a paragraph of text which is then repetitions of numerous keywords. The page will be not even close to accessible, and, to put it mildly, would be found quite annoying.
What exactly is an Alt attribute?

An ALT attribute shouldn't be used like a description or a label for an image, though lots of people utilize it in that fashion. Although it might seem natural to assume that alternate text is a label or perhaps a description, it is not!

The words used inside an image's alt attribute ought to be its text equivalent and convey the same information or serve exactly the same purpose that the image would.

The goal would be to provide the same functional information that the visual user would see. The alt attribute text should function as a "stand in" when the image itself is not available. Ask yourself this: If you were to replace the image using the text, would most users receive the same basic information, and wouldn't it create the same response?
Some examples:

Some SEO Optimization Tips

If your search button is really a magnifying glass or binoculars its alt text ought to be 'search' or 'find' not 'magnifying glass' or 'binoculars'.

If an image is supposed to convey the literal items in the look, a description is appropriate.

If it is designed to convey data, then that information is what's appropriate.

If it is meant to convey using a function, then your function itself is what should be used.

Some Alt Attribute Guidelines:

Always add alt attributes to images. Alt is mandatory for accessibility and for valid XHTML.

For images that play merely a decorative role in the page, make use of an empty alt (i.e. alt="") or a CSS background image so that reading browsers do not bother users by uttering things like "spacer image".

Remember that it's the function of the image we're trying to convey. For instance; any button images should not include the word "button" in the alt text. They ought to emphasize the action performed by the button.

Alt text ought to be determined by context. The same image in a different context may need drastically different alt text.

Attempt to flow alt text with the rest from the text because that is how it is going to be read with adaptive technologies like screen readers. Someone listening to your page should hardly remember that a graphic image is there.
Please keep in mind that utilizing an alt attribute for every image is required to meet the minimum WAI requirements, which are used as the benchmark for accessibility laws in UK and also the remainder of Europe. They are also necessary to meet "Section 508" accessibility requirements in america.

It is important to categorize non-text content into three levels:

Eye-Candy
Mood-Setting
Content and Function

I. Eye-Candy

Eye-Candy are things that serve no purpose other than to make a site visually appealing/attractive and (in many cases) fulfill the marketing departments. There isn't any content value (though there might be value to a sighted user).

Never alt-ify eye-candy unless there is something there which will enhance the usability of the site for someone utilizing a non-visual user agent. Make use of a null alt attribute or background images in CSS for eye-candy.

II. Mood-Setting

This is actually the middle layer of graphics which might serve to set the mood or set happens as it were. These graphics are not direct content and could 't be considered essential, but they're important in that they help frame what's going on.

Attempt to alt-ify the 2nd group as makes sense and it is relevant. There might be times when doing this might be annoying or detrimental to other users. Then try to avoid it.

For example; Alt text that is identical to adjacent text is unnecessary, and an irritant to screen reader users. I recommend alt="" or background CSS images in such instances. But sometimes, it's important to understand this content inside for those users.

Most times this will depend on context. The same image in a different context may need drastically different alt text. Obviously, content ought to always be fully available. The way you go in this example is really a judgment call.

III. Content and Function

This is where the image is the actual content. Always alt-ify content and functional images. Title and long description attributes may also be in order.
The main reason many authors can't understand why their alt text isn't working is they don't know why the images are there. You have to figured out exactly what function a picture serves. Consider what it's concerning the image that's important to the page's intended audience.

Every graphic has a reason behind being on that page: since it either enhances the theme/ mood/ atmosphere or it is critical to what the page is attempting to describe. Knowing what the image is for makes alt text simpler to write. And practice writing them definitely helps.
A way to look into the usefulness of alternative text is to imagine reading the page on the phone to someone. What would you say when encountering a particular image to make the page understandable to the listener?

Besides the alt attribute you've got a couple more tools available for images.
First, in degree of descriptiveness title is within between alt and longdesc. It adds useful information and may add flavor. The title attribute is optionally rendered by the user agent. Remember they're invisible and not shown like a "tooltip" when focus is received through the keyboard. (So much for device independence). So use the title attribute only for advisory information.
Second, the longdesc attribute points towards the Link to a complete description of the image. When the information found in a picture is important to the meaning of the page (i.e. some important content would be lost if the image was removed), a longer description compared to "alt" attribute can reasonably display ought to be used. It may provide for rich, expressive documentation of a visual image.

It ought to be used when alt and title are insufficient to embody the visual qualities of the image. As Clark [1] states, "A longdesc is a long description of an image...The goal is by using any length of description essential to impart the facts of the graphic.

It would not be remiss to hope that a long description conjures a picture - the look - within the mind's eye, an analogy that holds true even for the totally blind."

Although the alt attribute is mandatory for web accessibility and for valid (X)HTML, not every images need alternative text, long descriptions, or titles.

In many cases, you're best just choosing your gut instinct -- if it's not necessary to incorporate it, and when you don't possess a strong urge to do it, don't include that longdesc.

However, if it's necessary for the whole page to work, then you have to include the alt text (or title or longdesc).

What's necessary and what's not depends a great deal on the function of your image and its context on the page.

The same image may require alt text (or title or longdesc) in a single spot, although not in another. If an image provides absolutely no content or functional information alt="" or background CSS images might be appropriate to make use of. However, if the image provides content or adds functional information an alt would be required and perhaps a long description would be so as. In many cases this kind of thing is a judgement call.