About Me 0108: Alt Attribute & Search engine optimization

SEO Optimization images is becoming increasingly more essential in SEO (Seo optimization) for websites. The ALT attribute is a critical step that is often overlooked. This is often a lost opportunity for better rankings.

In Google's webmaster guidelines, they advise the use of alternative text for the images on your web 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 do that? The answer is easy, really; search engines have the same problem as blind users. They cannot see the images.

Many webmasters and inexperienced or unethical SEOs abuse the use of this attribute, trying to stuff it with keywords, hoping to achieve a particular keyword density, which is not 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 create a penalty for your site's ranking. Even without such a penalty, your site's rankings will not take advantage of this plan.
This process also puts persons who use screen readers at a greater disadvantage. Screen readers are software-based tools that really read aloud the items in what is shown on the screen. In browsing the net, the alt features of images are read aloud too.

Imagine hearing a paragraph of text that is then repetitions of numerous keywords. The page would be far from accessible, and, to put it bluntly, would be found quite annoying.
What is an Alt attribute?

An ALT attribute shouldn't be used like a description or a label to have an image, though many people utilize it for the reason that fashion. Although it may appear natural to assume that alternate text is really a label or perhaps a description, it is not!

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

The thing is to provide the same functional information that the visual user would see. The alt attribute text should be the "stand in" when the image is not available. Ask yourself this question: Should you replace the look using the text, would most users receive the same basic information, and would it generate the same response?
A few examples:

Some SEO Optimization Tips

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

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

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

If it's meant to convey using a function, then your function itself is what ought to 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 to ensure that reading browsers don't bother users by uttering such things as "spacer image".

Remember that it is the function from the image we are attempting to convey. For example; any button images should not include the word "button" within the alt text. They ought to emphasize the action performed through the button.

Alt text should be based on context. Exactly the same image in a different context may need drastically different alt text.

Try to flow alt text with the rest of the text because that's the way 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 using an alt attribute for every image is needed to satisfy the minimum WAI requirements, which are used as the benchmark for accessibility laws in UK and 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 other than to make a site visually appealing/attractive and (in many cases) satisfy the marketing departments. There isn't any content value (though there might be value to some sighted user).

Never alt-ify eye-candy unless there's something there that will boost the usability of the site for someone utilizing a non-visual user agent. Use 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 atmosphere or set the stage so to speak. These graphics aren't direct content and could 't be considered essential, but they are important in that they help frame what's going on.

Try to alt-ify the 2nd group as is sensible and it is relevant. There might be times when doing so might be annoying or detrimental with other users. Then avoid it.

For instance; 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 cases. But sometimes, it's vital that you understand this content in there for those users.

Most times it depends on context. The same image inside a different context may need drastically different alt text. Obviously, content should always be fully available. How you use this case is really 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 may also be in order.
The reason many authors can't understand why their alt text isn't working is they don't know why the images exist. You need to figured out exactly what function an image serves. Consider what it's about the image that's vital that you the page's intended audience.

Every graphic includes a reason behind standing on that page: since it either improves the theme/ mood/ atmosphere or it is advisable to what the page is trying to explain. Understanding what the image is perfect for makes alt text easier to write. And practice writing them definitely helps.
A way to check the usefulness of alternative text would be to imagine reading the page over the telephone to someone. An amount you say when encountering a specific image to create the page understandable to the listener?

Besides the alt attribute you've got a couple more tools at your disposal for images.
First, in degree of descriptiveness title is in between alt and longdesc. It adds useful information and can add flavor. The title attribute is optionally rendered by the user agent. Remember they're invisible and never shown as a "tooltip" when focus is received through the keyboard. (A lot for device independence). So make use of the title attribute just for advisory information.
Second, the longdesc attribute points to the Link to a complete description of an image. If the information found in a picture is essential to the meaning of the page (i.e. some important content would be lost when the image was removed), an extended description than the "alt" attribute can reasonably display ought to be used. It may provide for rich, expressive documentation of a visual image.

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

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

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

In many cases, you're better off just choosing your gut instinct -- if it's not essential to incorporate it, and if you don't have a strong urge to get it done, don't add that longdesc.

However, if it's essential for the entire page to work, then you have to add the alt text (or title or longdesc).

What's necessary and what's not depends a lot on the function of the image and it is context about the page.

Exactly the same image may require alt text (or title or longdesc) in a single spot, but not in another. If the image provides simply no content or functional information alt="" or background CSS images might be appropriate to make use of. But if the image provides content or adds functional information an alt will be required and maybe even a long description would be in order. Oftentimes this type of thing is a judgement call.