SEO Optimization images is becoming increasingly more essential in SEO (Search Engine Optimization) for websites. The ALT attribute is a critical step that is often overlooked. This can be a lost chance of better rankings.
In Google's webmaster guidelines, they advise using alternative text for that images in your site:
Images:. Use the alt attribute to provide descriptive text. Additionally, we recommend using a human-readable caption and descriptive text around the image.
Why would they ask us to achieve 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 the use of this attribute, trying to stuff it with keywords, hoping to achieve a certain keyword density, which isn't as relevant for rankings now since it once was.
On the contrary, high keyword density can, on some search engines like google, trigger spam filters, which might 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 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 displayed on the screen. In browsing the net, the alt features of images are read aloud as well.
Imagine listening to a paragraph of text that is followed by repetitions of many keywords. The page would be far from accessible, and, to put it mildly, would be found quite annoying.
What exactly is an Alt attribute?
An ALT attribute should not be used as a description or perhaps a label to have an image, though many people utilize it for the reason that fashion. Though it might seem natural to assume that alternate text is a label or a description, it's not!
What used inside an image's alt attribute should be its text equivalent and convey exactly the same information or serve the same purpose that the image would.
The thing would be to supply the same functional information that a visual user would see. The alt attribute text should function as a "stand in" in the event that the look itself is unavailable. Ask yourself this question: If you were to replace the image with the text, would most users receive the same basic information, and would it create the same response?
A few examples:
Some SEO Optimization Tips
If your search button is a magnifying glass 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 the use of 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 within the page, use an empty alt (i.e. alt="") or perhaps a CSS background image so that reading browsers do not bother users by uttering things like "spacer image".
Remember that it is the function of the image we're attempting to convey. For example; any button images should not range from the word "button" in the alt text. They ought to emphasize the action performed by the button.
Alt text should be determined by context. Exactly the same image inside a different context may require drastically different alt text.
Try to flow alt text with the rest from the text because that is the way it will be read with adaptive technologies like screen readers. Someone listening to your page should hardly be aware that a graphic image is there.
Please keep in mind that utilizing an alt attribute for every image is required 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 the US.
It is important to categorize non-text content into three levels:
Content and Function
Eye-Candy are things that serve no purpose apart from to make a site visually appealing/attractive and (oftentimes) fulfill 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 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.
This is actually the middle layer of graphics which may actually set the atmosphere or set happens so to speak. These graphics are not direct content and could 't be considered essential, but they're essential in that they help frame what is going on.
Attempt to alt-ify the 2nd group as is sensible and it is relevant. There may be times when doing so 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, and an irritant to screen reader users. I suggest alt="" or background CSS images in such instances. But sometimes, it's vital that you get this content inside for those users.
Usually this will depend on context. The same image inside a different context may require drastically different alt text. Obviously, content should always be fully available. The way you go in 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 so as.
The reason many authors can't understand why their alt text isn't working is that they don't know why the pictures exist. You need to figured out precisely what function an image serves. Think about 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: because it either improves the theme/ mood/ atmosphere or it is advisable to what are the page is attempting to explain. Knowing 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. An amount you say when encountering a specific image to create the page understandable to the listener?
Besides the alt attribute you've got a couple more tools at your disposal 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 through the user agent. Remember they're invisible and never 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 an image. If the information found in a picture is important to the concept of the page (i.e. some important content will be lost if the image was removed), a longer description compared to "alt" attribute can reasonably display should be used. It can offer rich, expressive documentation of a visual image.
It ought to be used when alt and title are insufficient to embody the visual qualities of the image. As Clark  states, "A longdesc is a long description of an image...The goal is by using any period of description necessary to impart the details from the graphic.
It would not be remiss to hope that a long description conjures a picture - the look - within the mind's eye, an analogy that is true even for the 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.
In many cases, you're better off 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 add 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 lot on the function of your image and it is context on the page.
The same image may need alt text (or title or longdesc) in one spot, although not in another. If an image provides absolutely no content or functional information alt="" or background CSS images might be appropriate to use. But if the image provides content or adds functional information an alt will be required and maybe even a long description would be so as. Oftentimes this type of thing is a judgement call.
Listed below are key steps 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. Stay away from underscores as a word separator, like for example "brilliant-diamonds.jpg";
Label the file extension. For example, when the image internet search engine sees a ".jpg" (JPEG) file extension, it's likely to assume that the file is a photo, and when it sees a ".gif" (GIF) file extension, it's likely to assume that it is graphic;
Make sure that the text nearby the image that is relevant to that image.
Again, do not lose an excellent chance to help your site together with your images in search engines. Use these steps to position better on all of the engines and drive more traffic for your site TODAY.