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 on your web site:

Images:. Use the alt attribute to provide descriptive text. In addition, 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 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, attempting to stuff it with keywords, hoping 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, 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 in a greater disadvantage. Screen readers are software-based tools that actually read aloud the contents of what's displayed 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 followed by repetitions of many keywords. The page would be not even close to accessible, and, to put it bluntly, would be found quite annoying.
What exactly is an Alt attribute?

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

What used within an image's alt attribute ought to be its text equivalent and convey the same information or serve exactly the same purpose that the image would.

The goal 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 image is not available. Think about this: Should you replace the look with the text, would most users get the same basic information, and wouldn't it create the same response?
A few examples:

 

Some SEO Optimization Tips

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

If an image is meant to convey the literal contents of the image, a description is appropriate.

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

If it is meant to convey using a function, then the function is what ought to be used.

Some Alt Attribute Guidelines:

Always add alt attributes to images. Alt is mandatory for accessibility as well as for valid XHTML.

For images that play merely a decorative role in the page, use an empty alt (i.e. alt="") or a CSS background image so that reading browsers do not bother users by uttering things like "spacer image".

Remember that it's the function from the image we're attempting to convey. For example; any button images shouldn't range from the word "button" within the alt text. They ought to emphasize the action performed by 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 rest of the text because that is the way it will be read with adaptive technologies like screen readers. Someone hearing your page should hardly remember 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 as the benchmark for accessibility laws in UK and also the rest of Europe. Also, they are required to meet "Section 508" accessibility requirements in america.

It is important 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 that will boost the usability of the site for somebody using 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 might actually set the atmosphere or set happens so to speak. These graphics aren't direct content and could not be considered essential, but they are important in that 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 try to avoid it.

For example; Alt text that's identical to 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 important to understand this content inside for those 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. How you use 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 can also be in order.
The reason many authors can't figure out why their alt text isn't working is that they don't know why the pictures are there. You have to figured out precisely what function an image serves. Consider what it is about the image that's important to the page's intended audience.

Every graphic has a reason for standing on that page: since it either enhances the theme/ mood/ atmosphere or it is critical to what the page is attempting to explain. Knowing what the look is 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 over the telephone to someone. An amount you say when encountering a particular image to make the page understandable to the listener?

Besides the alt attribute you have a couple more tools available for images.
First, in level of descriptiveness title is in 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 through 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 the image. When the information contained in a picture is important towards the concept of the page (i.e. some important content would be lost if the image was removed), a longer description than the "alt" attribute can reasonably display ought to be used. It may provide for rich, expressive documentation of the visual image.

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

It wouldn't 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 as well as for valid (X)HTML, not every images need alternative text, long descriptions, or titles.

Oftentimes, you're best 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 add 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 the image and its context about the page.

The same image may need alt text (or title or longdesc) in one spot, although not in another. If an image provides simply 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 maybe even a long description will be in order. Oftentimes this kind of thing is really a judgement call.

Image Seo 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 example, when the image search engine sees a ".jpg" (JPEG) file extension, it's likely to assume that the file is really a photo, and when it sees a ".gif" (GIF) file extension, it's likely to assume that it is graphic;

Ensure that the written text at the image that is highly relevant to that image.
Again, do not lose an excellent chance to help your website with your images in search engines. Use these steps to rank better on all the engines and drive increased traffic for your site TODAY.

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