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 often overlooked. This can be a lost opportunity for better rankings.


In Google's webmaster guidelines, they advise using alternative text for the images on your 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 do that? The answer is simple, really; search engines have the same problem as blind users. They can't begin to see the images.

Many webmasters and inexperienced or unethical SEOs abuse using this attribute, attempting to stuff it with keywords, hoping to achieve a certain keyword density, which is not as relevant for rankings now since it was previously.

On the contrary, high keyword density can, on some search engines, trigger spam filters, which may result in a penalty for your 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 in a greater disadvantage. Screen readers are software-based tools that actually read aloud the contents of what's shown on the screen. In browsing the web, the alt attributes of images are read aloud too.

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

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

The words used within an image's alt attribute should be its text equivalent and convey the same information or serve the same purpose that the image would.

The goal is to supply 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 is unavailable. 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?
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 suitable.

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

If it's meant to convey the use of 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 as well as for valid XHTML.

For images that play only a decorative role within the page, use an empty alt (i.e. alt="") or perhaps a CSS background image so that reading browsers don't bother users by uttering such things as "spacer image".

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

Alt text should be determined by 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 how it will be read with adaptive technologies like screen readers. Someone listening to your page should hardly remember that a graphic image can there be.
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 also the remainder of Europe. They are also necessary 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 stuff that serve no purpose other than to create a site visually appealing/attractive and (oftentimes) fulfill the marketing departments. There is no content value (though there might be value to a sighted user).

Never alt-ify eye-candy unless there's something there which will boost the usability from the site for someone 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 might serve to set the mood or set the stage as it were. These graphics are not direct content and could 't be considered essential, but they're essential in that they help frame what's going on.

Try to alt-ify the 2nd group as makes sense and it is relevant. There may be times when doing this may be annoying or detrimental with other users. Then avoid it.

For instance; Alt text that is 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 all users.

Most times it depends on context. The same image inside a different context may require drastically different alt text. Obviously, content ought to always be fully available. The way you use 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 understand why their alt text isn't working is they don't know why the images exist. You need to determined precisely what function an image serves. Consider what it is about the image that's vital that you the page's intended audience.

Every graphic has a reason behind standing on that page: since it either enhances the theme/ mood/ atmosphere or it is critical to what are the page is trying to explain. Understanding 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 is to imagine reading the page on the phone to someone. What would 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 never shown like a "tooltip" when focus is received via the keyboard. (A lot for device independence). So use the title attribute just for advisory information.
Second, the longdesc attribute points to the URL of a full description of an image. If the information contained in an image is important to the meaning of the page (i.e. some important content will be lost if the image was removed), an extended description compared to "alt" attribute can reasonably display should be used. It may offer rich, expressive documentation of a visual image.

It should 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 aim is to use any period of description necessary to impart the details from the graphic.

It would not be remiss to hope that the long description conjures a picture - the image - in the mind's eye, an analogy that holds true even for that totally blind."

Even though alt attribute is mandatory for web accessibility and for valid (X)HTML, not all images need alternative text, long descriptions, or titles.

In many cases, 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 get it done, don't include that longdesc.

However, if it's essential 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 great deal on the function of your image and it is context about the page.

The same image may need alt text (or title or longdesc) in one spot, but not in another. If the image provides absolutely no content or functional information alt="" or background CSS images might be appropriate to make use of. However, if the image provides content or adds functional information an alt will be required and maybe a long description will be in order. In many cases this type of thing is a judgement call.

Image Search Engine Optimization Tips


Listed here are key stages in optimizing images:

Choose 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 as a word separator, like for example "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 that the file is really a photo, and when it sees a ".gif" (GIF) file extension, it's going to assume that it is graphic;

Ensure that the written text nearby the image that's highly relevant to that image.
Again, do not lose an excellent chance to help your site together with your images searching engines. Begin using these steps to rank better on all of the engines and drive increased traffic for your site TODAY.

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