About Me 0015: Alt Attribute & Search engine optimization

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

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

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

Why would they ask us to do that? The answer is simple, 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, attempting to stuff it with keywords, looking to achieve a particular keyword density, which isn't as relevant for rankings now since it was previously.

On the other hand, high keyword density can, on some search engines like google, trigger spam filters, which may result in a penalty for the site's ranking. Even without this type of 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 really read aloud the contents of what is shown on the screen. In browsing the net, the alt features of images are read aloud as well.

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

An ALT attribute should not be used as a description or a label to have an image, though many people utilize it in that fashion. Though it might seem natural to assume that alternate text is a label or perhaps a description, it's 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 the image would.

The goal would be to supply 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 unavailable. Think about this question: Should you replace the image with the text, would most users receive the same basic information, and would it create the same response?
Some examples:

Some SEO Optimization Tips

If your 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 items in the look, a description is appropriate.

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

If it is designed to convey using a function, then the 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 within the page, make use of an empty alt (i.e. alt="") or perhaps a CSS background image to ensure that reading browsers do not bother users by uttering such things as "spacer image".

Remember that it's the function of the image we are trying to convey. For example; any button images shouldn't include the word "button" in the alt text. They ought to emphasize the action performed through the button.

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

Attempt to flow alt text with the remainder from the text because that is the way it is going to be read with adaptive technologies like screen readers. Someone hearing your page should hardly be aware that a graphic image can there be.
Please remember that utilizing an alt attribute for each image is needed to meet the minimum WAI requirements, which are used since the benchmark for accessibility laws in UK and also the remainder of Europe. Also, they are necessary to meet "Section 508" accessibility requirements in the US.

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

Eye-Candy
Mood-Setting
Content and Function

I. Eye-Candy

Eye-Candy are stuff that serve no purpose other than to make a site visually appealing/attractive and (in many cases) fulfill the marketing departments. There is no content value (though there might be value to some sighted user).

Never alt-ify eye-candy unless there's something there that will enhance the usability from the site for somebody 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 actually the middle layer of graphics which may serve to set the mood or set the stage so to speak. These graphics aren't direct content and may not be considered essential, but they're important in they help frame what is going on.

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

For instance; Alt text that's just like 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 vital that you understand this content inside for those users.

Usually this will depend on context. Exactly 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 look may be 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 they don't know why the pictures are there. You have to determined exactly what function a picture serves. Consider what it's 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 trying to describe. Knowing what the look 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 on the phone to someone. What would 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 through 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 make use of the title attribute only for advisory information.
Second, the longdesc attribute points to the Link to a complete description of an image. When the information found in a picture is essential to the concept of the page (i.e. some important content will be lost if the image was removed), a longer description compared to "alt" attribute can reasonably display should be used. It can offer rich, expressive documentation of a 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 aim is to use any length of description essential to impart the details from the graphic.

It would not be remiss to hope that a long description conjures an image - 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 as well as for valid (X)HTML, not every images need alternative text, long descriptions, or titles.

In many cases, you're better off just going with your gut instinct -- if it's not necessary to include it, and if you don't have a strong urge to do it, don't include that longdesc.

However, if it's necessary 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 about 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, but not in another. If an image provides absolutely no content or functional information alt="" or background CSS images might be appropriate to use. However, if the image provides content or adds functional information an alt will be required and maybe a long description would be in order. In many cases this type of thing is really a judgement call.