clear42: Alt Attribute & SEO Optimization

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

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

Images:. Use 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 simple, really; search engines like google have the same problem as blind users. They cannot begin to see the images.

Many webmasters and inexperienced or unethical SEOs abuse using this attribute, attempting to stuff it with keywords, looking to achieve a particular 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, trigger spam filters, which may result in a penalty for your site's ranking. Even without such a penalty, your site's rankings will not benefit from this tactic.
This process also puts persons who use screen readers in a greater disadvantage. Screen readers are software-based tools that really read aloud the items in what's displayed on the screen. In browsing the net, the alt features of images are read aloud as well.

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

An ALT attribute shouldn't be used like a description or perhaps a label to have an image, though many people use it in that fashion. Though 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 supply the same functional information that the visual user would see. The alt attribute text should be the "stand in" in the event that the image itself is unavailable. Think about this: If you were to replace the look using the text, would most users receive the same basic information, and would it create the same response?
A few examples:

Some SEO Optimization Tips

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

If an image is meant to convey the literal contents of the look, a description is suitable.

If it is meant to convey data, then that data is what is appropriate.

If it's designed to convey using a function, then the function is what ought to be used.

Some Alt Attribute Guidelines:

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

For images that play only a decorative role within the page, use an empty alt (i.e. alt="") or perhaps a CSS background image to ensure that reading browsers do not bother users by uttering things like "spacer image".

Keep in mind that it's the function from the image we're attempting to convey. For example; any button images shouldn't include the word "button" in the alt text. They should emphasize the action performed through the button.

Alt text ought to be determined by context. Exactly the same image inside a different context may need drastically different alt text.

Try to flow alt text with the remainder of the text because that is how it will 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 using an alt attribute for each image is needed to satisfy the minimum WAI requirements, which are used as the benchmark for accessibility laws in UK and also the rest of Europe. Also, they are required to meet "Section 508" accessibility requirements in the US.

It is useful 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 apart from to make a site visually appealing/attractive and (in many cases) satisfy the marketing departments. There isn't any content value (though there may be value to some sighted user).

Never alt-ify eye-candy unless there is something there which will boost the usability of the site for someone using 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 the middle layer of graphics which might serve to set the atmosphere or set happens so to speak. These graphics are not direct content and could 't be considered essential, but they are important in they help frame what's going on.

Attempt to alt-ify the second group as is sensible and it is relevant. There may be times when doing so might be annoying or detrimental to other users. Then avoid it.

For instance; Alt text that's just like adjacent text is unnecessary, as well as an irritant to screen reader users. I suggest alt="" or background CSS images in such cases. But sometimes, it's vital that you understand this content in there for those users.

Most times this will depend on context. Exactly the same image inside a different context may require drastically different alt text. Obviously, content ought to always be fully available. How you go in this example is a judgment call.

III. Content and Function

This is when the look is the actual content. Always alt-ify content and functional images. Title and long description attributes can also be in order.
The main reason many authors can't figure out why their alt text isn't working is that they don't know why the images are there. You have to figured out exactly what function an image serves. Think about what it is concerning the image that's vital that you the page's intended audience.

Every graphic includes a reason behind being on that page: since it either improves the theme/ mood/ atmosphere or it is advisable to what the page is attempting to explain. Knowing what the look 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 over the telephone to someone. What would you say when encountering a specific image to make the page understandable towards the listener?

Besides the alt attribute you have a couple more tools at your disposal for images.
First, in level of descriptiveness title is in between alt and longdesc. It adds useful information and may add flavor. The title attribute is optionally rendered by the user agent. Remember they are invisible and not shown like a "tooltip" when focus is received via the keyboard. (A lot for device independence). So use the title attribute only for advisory information.
Second, the longdesc attribute points to the URL of a complete description of the image. If the information found in an image is important to the meaning of the page (i.e. some important content would be lost when the image was removed), a longer description than the "alt" attribute can reasonably display ought to be used. It can provide for rich, expressive documentation of the visual image.

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

It would not be remiss to hope that the long description conjures a picture - the image - in the mind's eye, an analogy that holds true even for that 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 going with your gut instinct -- if it's not essential to include it, and when you don't have a strong urge to do it, don't add that longdesc.

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

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

The same image may need alt text (or title or longdesc) in a single spot, although not in another. If the image provides simply no content or functional information alt="" or background CSS images may 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 in order. In many cases this kind of thing is really a judgement call.