About Me 0091: Alt Attribute & Search engine optimization

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

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

Images:. Make use of the alt attribute to supply 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 have the same problem as blind users. They cannot begin to 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, trigger spam filters, which might create a penalty for the site's ranking. Even without such a penalty, your site's rankings won't benefit from this plan.
This method also puts persons who use screen readers at a greater disadvantage. Screen readers are software-based tools that actually read aloud the contents of 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 that is then repetitions of many keywords. The page would 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 should not be used like a description or perhaps a label for an image, though lots of people utilize it for the reason that fashion. Though it may appear natural to assume that alternate text is really a label or perhaps a description, it's not!

What used within an image's alt attribute should be its text equivalent and convey exactly the same information or serve the same purpose 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" when the look is not available. Think about this: Should you replace the image using the text, would most users receive the same basic information, and would it create the same response?
Some examples:

Some SEO Optimization Tips

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

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

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

If it is designed to convey using a function, then your function 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 perhaps 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 shouldn't include the word "button" within the alt text. They should emphasize the action performed through the button.

Alt text ought to be based on context. The same image inside a different context may require drastically different alt text.

Try to flow alt text with the remainder from the text because that's the way it will be read with adaptive technologies like screen readers. Someone hearing your page should hardly be aware that a graphic image is there.
Please remember that utilizing an alt attribute for every image is needed to meet the minimum WAI requirements, which are used as the benchmark for accessibility laws in UK and the remainder of Europe. They are also necessary 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 is no content value (though there may be value to a sighted user).

Never alt-ify eye-candy unless there's something there that will enhance the usability of the site for somebody utilizing a non-visual user agent. Use a null alt attribute or background images in CSS for eye-candy.

II. Mood-Setting

This is the middle layer of graphics which may serve to set the atmosphere or set the stage so to speak. These graphics are not direct content and may 't be considered essential, but they are important in they help frame what is going on.

Try to alt-ify the 2nd group as is sensible and is relevant. There might be times when doing so might be annoying or detrimental to 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 get this content inside for all users.

Usually 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. The way you go in this case 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 may also be so as.
The 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 determined precisely what function a picture serves. Consider what it's about the image that's important to the page's intended audience.

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

Aside from the alt attribute you've got a couple more tools at your disposal for images.
First, in degree of descriptiveness title is within between alt and longdesc. It adds useful information and can 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. (So much for device independence). So make use of the title attribute only for advisory information.
Second, the longdesc attribute points towards the Link to a full description of an image. If the information found in a picture is essential towards the meaning of the page (i.e. some important content will be lost if the image was removed), an extended description than the "alt" attribute can reasonably display ought to be used. It may offer rich, expressive documentation of the visual image.

It ought to 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 the image...The goal is to use any length of description essential to impart the facts from the graphic.

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

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

Oftentimes, you're best just going with your gut instinct -- if it's not necessary to incorporate it, and if you don't have a strong urge to do it, don't add that longdesc.

However, if it's necessary for the entire 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 about the function of the image and its context on the page.

The same image may need alt text (or title or longdesc) in one spot, although 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. However, if the image provides content or adds functional information an alt will be required and perhaps a long description would be in order. In many cases this type of thing is a judgement call.