haileycajp: Alt Attribute & Search engine optimization

SEO Optimization images has become increasingly 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 the use of alternative text for that images on 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 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, looking to achieve a certain keyword density, which isn't as relevant for rankings now since it once was.

On the other hand, high keyword density can, on some search engines like google, 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 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 is displayed on the screen. In browsing the web, 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 would be far from accessible, and, to put it bluntly, will be found quite annoying.
What exactly is an Alt attribute?

An ALT attribute shouldn't be used like a description or a label to have an image, though many people utilize it in that fashion. Although it might seem natural to assume that alternate text is a label or perhaps a description, it is not!

The words used inside 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 is to provide the same functional information that the visual user would see. The alt attribute text should function as a "stand in" when the image itself is unavailable. Ask yourself this: If you were to replace the image with the text, would most users receive the same basic information, and wouldn't it generate the same response?
Some examples:

Some SEO Optimization Tips

If your search button is really 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 items in the image, a description is suitable.

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

If it's meant to convey using a function, then your 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 within 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 such things as "spacer image".

Remember that it is the function from the image we are trying to convey. For instance; any button images shouldn't include the word "button" in the alt text. They should emphasize the action performed by the button.

Alt text should be determined by context. Exactly the same image inside a different context may need drastically different alt text.

Try to flow alt text with the rest from the text because that's how 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 remember that using an alt attribute for every image is needed to meet the minimum WAI requirements, which are used as 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 some sighted user).

Never alt-ify eye-candy unless there's something there which will boost the usability of 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 the middle layer of graphics which might serve to set the atmosphere or set happens as it were. These graphics are not direct content and could 't be considered essential, but they are essential in that they help frame what's going on.

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

For instance; Alt text that's just like adjacent text is unnecessary, as well as 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 in there for those users.

Usually this will depend on context. Exactly the same image in a different context may need 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 can also be so as.
The main 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 determined exactly what function an image serves. Consider what it is about the image that's vital that you the page's intended audience.

Every graphic includes a reason for standing on that page: because it either improves the theme/ mood/ atmosphere or it is critical to what the page is attempting to explain. Understanding what the look is for makes alt text simpler to write. And practice writing them definitely helps.
A way to check the usefulness of alternative text would be to imagine reading the page over the telephone to someone. What would you say when encountering a specific image to create the page understandable to the listener?

Aside from the alt attribute you have a couple more tools at your disposal for images.
First, in degree of descriptiveness title is within between alt and longdesc. It adds useful information and can add flavor. The title attribute is optionally rendered by 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 towards the Link to a full description of the image. If the information contained in an image is essential towards the concept of the page (i.e. some important content would be lost when the image was removed), a longer description compared to "alt" attribute can reasonably display should be used. It can 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 a long description of an image...The goal is by using any period of description essential to impart the details from 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 the totally blind."

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

Oftentimes, you are better off just choosing your gut instinct -- if it's not necessary 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 essential for the entire page to work, then you've 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.

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