Friday, April 22, 2011

Alt Attribute & Search engine optimization

SEO Optimization images has become more and more essential in SEO (Seo 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 the use of alternative text for that images on your site:

Images:. Use the alt attribute to supply descriptive text. In addition, we recommend using a human-readable caption and descriptive text around 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 see the images.

Many webmasters and inexperienced or unethical SEOs abuse using this attribute, trying 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 contrary, high keyword density can, on some search engines, trigger spam filters, which might create a penalty for the site's ranking. Even without this type of penalty, your site's rankings will not 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 items in 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 numerous keywords. The page will be far from accessible, and, to put it mildly, will be found quite annoying.
What exactly is an Alt attribute?

An ALT attribute should not be used as a description or a label to have an image, though lots of people use it in that fashion. Although it might seem natural to assume that alternate text is a label or a description, it is not!

The words used within an image's alt attribute ought to be its text equivalent and convey the same information or serve exactly 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 function as a "stand in" in the event that the image itself is unavailable. Ask yourself this: If you were to replace the look using 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 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 meant to convey the literal items in the image, then a description is suitable.

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

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

Remember that it is the function from the image we're trying to convey. For example; any button images should not include the word "button" in the alt text. They should emphasize the action performed through the button.

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

Try to flow alt text with the remainder of the text because that is how it will be read with adaptive technologies like screen readers. Someone listening to your page should hardly remember that a graphic image is there.
Please remember that using an alt attribute for each image is needed to satisfy the minimum WAI requirements, which are used as the benchmark for accessibility laws in UK and the rest 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 things that serve no purpose apart from to create a site visually appealing/attractive and (oftentimes) fulfill the marketing departments. There isn't any content value (though there might be value to some sighted user).

Never alt-ify eye-candy unless there is something there that will enhance the usability from 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 mood or set happens as it were. These graphics aren't direct content and may 't be considered essential, but they are important in that they help frame what is going on.

Try to alt-ify the second group as makes sense and it is relevant. There may be instances 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 understand this content in there for those users.

Usually it depends 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 use 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 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 images are there. You have to figured out precisely what function a picture serves. Think about what it's about the image that's important to the page's intended audience.

Every graphic includes a reason behind standing on that page: because it either improves the theme/ mood/ atmosphere or it is critical to what the page is trying to describe. Knowing what the image is perfect for makes alt text simpler to write. And exercise writing them definitely helps.
A method 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 towards the listener?

Aside from the alt attribute you've got a couple more tools at your disposal for images.
First, in level of descriptiveness title is in between alt and longdesc. It adds useful information and can add flavor. The title attribute is optionally rendered by the user agent. Remember they're invisible and never shown like a "tooltip" when focus is received via 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 Link to a complete description of the image. When the information contained in a picture is essential 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 should be used. It can 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 an image...The goal is by using any length of description essential to impart the facts of the graphic.

It wouldn't be remiss to hope that the long description conjures an image - the look - in the mind's eye, an analogy that is 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.

Oftentimes, you're better off just going with your gut instinct -- if it's not essential to incorporate it, and when 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 work, 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 it is context about the page.

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

Image Seo optimization Tips


Listed here are key steps in optimizing images:

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

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

Ensure that the text nearby the image that is relevant to that image.
Again, do not lose a great chance to help your site with your images in search engines. Use these steps to position better on all the engines and drive increased traffic for your site TODAY.

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