Friday, April 22, 2011

Alt Attribute & Seo

SEO Optimization images has become more and more important in SEO (Search Engine 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 using alternative text for the images on your 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 a similar problem as blind users. They can't 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 particular keyword density, which isn't as relevant for rankings now as it was previously.

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 in a greater disadvantage. Screen readers are software-based tools that really read aloud the items in what's shown on the screen. In browsing the web, the alt features of images are read aloud too.

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

An ALT attribute should not be used like a description or perhaps a label for an image, though many people utilize it for the reason that fashion. Although it might seem natural to assume that alternate text is a label or 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 provide the same functional information that the visual user would see. The alt attribute text should be the "stand in" in the event that the look itself is unavailable. Think about this: Should you replace the look using the text, would most users get the same basic information, and would it create the same response?
Some examples:

 

Some SEO Optimization Tips

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

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

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

If it is 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 so that reading browsers don't bother users by uttering things like "spacer image".

Keep in mind that it's 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 should emphasize the action performed through the button.

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

Try to flow alt text with the rest from the text because that's how it will be read with adaptive technologies like screen readers. Someone hearing your page should hardly remember 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, which are used since the benchmark for accessibility laws in UK and the remainder of Europe. They are also necessary 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 things that serve no purpose apart from to make a site visually appealing/attractive and (oftentimes) satisfy the marketing departments. There isn't any content value (though there might be value to a sighted user).

Never alt-ify eye-candy unless there's something there which will enhance the usability from the site for someone utilizing 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 actually set the mood or set the stage so to speak. These graphics aren't direct content and could not be considered essential, but they are essential in they help frame what's going on.

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

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

Usually it depends on context. Exactly the same image inside a different context may require drastically different alt text. Obviously, content should always be fully available. How you go in this case is a judgment call.

III. Content and Function

This is when the look may be the actual content. Always alt-ify content and functional images. Title and long description attributes may also be in order.
The main reason many authors can't understand why their alt text isn't working is they don't know why the images are there. You need to determined exactly what function an image serves. Consider what it is 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 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 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 on the phone to someone. An amount you say when encountering a particular image to make the page understandable towards the listener?

Besides the alt attribute you've got a couple more tools available for images.
First, in degree 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're invisible and not shown as a "tooltip" when focus is received through the keyboard. (So much for device independence). So make use of the title attribute just for advisory information.
Second, the longdesc attribute points towards the URL of a full description of the image. If the information contained in a picture 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 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 an image. As Clark [1] states, "A longdesc is a long description of an image...The goal 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 - in 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 best just going with your gut instinct -- if it's not essential to include it, and if you don't possess a strong urge to get it done, don't add that longdesc.

However, if it's necessary for the whole page to operate, then you have to add 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 about the page.

The same image may need alt text (or title or longdesc) in one spot, but not in another. If an image provides absolutely no content or functional information alt="" or background CSS images may be appropriate to use. But if the image provides content or adds functional information an alt would be required and perhaps even a long description will be in order. Oftentimes this kind of thing is really a judgement call.

Image Search Engine Optimization Tips


Listed below are key stages in optimizing images:

Select 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, such as "brilliant-diamonds.jpg";

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

Make sure that the text at the image that is relevant to that image.
Again, don't lose a great opportunity to help your site with your images in search engines. Use these steps to position better on all of the engines and drive increased traffic to your site TODAY.

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