Friday, April 22, 2011

Alt Attribute & Search engine optimization

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


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

Images:. Make use of the alt attribute to provide descriptive text. In addition, we recommend using a human-readable caption and descriptive text round 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 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 particular keyword density, which is not as relevant for rankings now since it once was.

On the contrary, high keyword density can, on some search engines, 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 method 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 as well.

Imagine listening to 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 perhaps a label for an image, though lots of people use it in that fashion. Although 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 the same information or serve the same purpose the image would.

The thing would be to provide the same functional information that the visual user would see. The alt attribute text should function as a "stand in" in the event that the look itself is unavailable. Think about this question: Should you replace the image 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 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 look, a description is suitable.

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

If it is meant to convey the use of 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 only a decorative role within the page, make use of an empty alt (i.e. alt="") or a CSS background image so that reading browsers don't bother users by uttering things like "spacer image".

Remember that it is the function from the image we're trying to convey. For instance; 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 ought to be based on context. The same image inside a different context may need drastically different alt text.

Attempt to flow alt text with the rest from the text because that's 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 is there.
Please keep in mind that utilizing an alt attribute for every image is needed to satisfy the minimum WAI requirements, that are used as the benchmark for accessibility laws in UK and the remainder of Europe. They are also required to meet "Section 508" accessibility requirements in america.

It is useful 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 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 enhance the usability from 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 actually the middle layer of graphics which might actually set the atmosphere or set the stage as it were. These graphics are not direct content and may 't be considered essential, but they are essential in that they help frame what is going on.

Attempt to alt-ify the second group as makes sense 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 suggest 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 use this example is 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 reason many authors can't understand why their alt text isn't working is that they don't know why the pictures are there. You have to determined precisely what function a picture serves. Consider what it's concerning the image that's vital that you the page's intended audience.

Every graphic has a reason behind being on that page: since it either improves the theme/ mood/ atmosphere or it is critical to what are the page is trying to describe. Understanding what the look is for makes alt text simpler to write. And exercise writing them definitely helps.
A method to look into the usefulness of alternative text is 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?

Aside from 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 through the user agent. Remember they are invisible and never shown as 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 full description of an image. When the information found in an image is important towards the meaning of the page (i.e. some important content will be lost when the image was removed), a longer description compared to "alt" attribute can reasonably display ought to be used. It may offer rich, expressive documentation of the 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 a long description of the image...The goal is to use any period of description essential to impart the details of the graphic.

It wouldn't be remiss to hope that a long description conjures a picture - the image - in the mind's eye, an analogy that is 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 choosing your gut instinct -- if it's not necessary to incorporate it, and if 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 add 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 one spot, although not in another. If an image provides absolutely no content or functional information alt="" or background CSS images may be appropriate to use. However, if the image provides content or adds functional information an alt will be required and perhaps even a long description will be in order. In many cases this kind of thing is really a judgement call.

Image Seo optimization Tips


Listed below are key steps in optimizing images:

Choose a logical file name that reinforces the keywords. You should use hyphens within the file name to isolate the keyword, but avoid to exceeding two hyphens. Avoid using underscores as a word separator, like for example "brilliant-diamonds.jpg";

Label the file extension. For instance, if the image internet search engine sees a ".jpg" (JPEG) file extension, it's going to assume the file is really a photo, and if it sees a ".gif" (GIF) file extension, it's likely to assume that it is graphic;

Make sure that the written text nearby the image that's highly relevant to that image.
Again, do not lose a great opportunity to help your site together with your images searching engines. Use these steps to position better on all the engines and drive more traffic to your site TODAY.

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