SEO Optimization images is becoming increasingly more important 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 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 cannot see the images.
Many webmasters and inexperienced or unethical SEOs abuse the use of this attribute, trying to stuff it with keywords, looking to achieve a particular 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 may create a penalty for the site's ranking. Even without this type of penalty, your site's rankings won't take advantage of 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 contents of what is 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 that is then repetitions of numerous keywords. The page will be not even close to accessible, and, to put it mildly, will be found quite annoying.
What is an Alt attribute?
An ALT attribute shouldn't be used as a description or a label for an image, though many people use it for the reason that fashion. Although it may appear 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 the same information or serve 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 be the "stand in" when the image is unavailable. Ask yourself this: Should you replace the look with the text, would most users get the same basic information, and would it create the same response?
Some SEO Optimization Tips
If your 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 items in the image, a description is suitable.
If it is designed to convey data, then that data is what's appropriate.
If it's designed 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 so that reading browsers don't bother users by uttering things like "spacer image".
Remember that it is the function of the image we are attempting to convey. For instance; any button images shouldn't range from the word "button" in the alt text. They ought to emphasize the action performed through the button.
Alt text ought to be based on context. Exactly the same image in a different context may require drastically different alt text.
Attempt to flow alt text with the remainder of the text because that's how 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 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 required to meet "Section 508" accessibility requirements in america.
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 (in many cases) 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 is something there that will enhance the usability of the site for somebody using a non-visual user agent. Make use of a null alt attribute or background images in CSS for eye-candy.
This is the middle layer of graphics which may actually set the mood or set happens so to speak. These graphics aren't direct content and may not 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 instances when doing so may be annoying or detrimental to other users. Then try to avoid it.
For example; Alt text that is 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 important to understand this content inside for those users.
Most times 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 go in this case is a judgment call.
III. Content and Function
This is when the image is 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 they don't know why the images are there. You need to determined precisely what function an image serves. Think about what it's concerning the image that's important to the page's intended audience.
Every graphic includes a reason for being on that page: because it either improves the theme/ mood/ atmosphere or it is advisable to what the page is trying to describe. Understanding what the look is for makes alt text simpler to write. And practice writing them definitely helps.
A method 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 particular image to create the page understandable to the listener?
Besides the alt attribute you've got 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 by the user agent. Remember they're invisible and not shown like a "tooltip" when focus is received through the keyboard. (A lot for device independence). So use the title attribute only for advisory information.
Second, the longdesc attribute points to the URL of a full description of the image. When the information contained in a picture is essential to the concept of the page (i.e. some important content would be lost if the image was removed), an extended description than the "alt" attribute can reasonably display should be used. It may provide for 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  states, "A longdesc is a long description of an image...The goal is to use 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 holds true even for the totally blind."
Although the 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 going with your gut instinct -- if it's not necessary to incorporate it, and when you don't possess a strong urge to do it, 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 lot on the function of the image and it is context on the page.
Exactly the same image may require 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 might be appropriate to make use of. But if the image provides content or adds functional information an alt will be required and maybe a long description would be so as. In many cases this kind of thing is really a judgement call.
Image Seo optimization Tips
Listed below 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. Stay away from underscores like a word separator, such as "brilliant-diamonds.jpg";
Label the file extension. For instance, if the image search engine sees a ".jpg" (JPEG) file extension, it's likely to assume that the file is a photo, and if it sees a ".gif" (GIF) file extension, it's going to assume that it is graphic;
Make sure that the written text nearby the image that's highly relevant to that image.
Again, don't lose a great opportunity to help your site together with your images searching engines. Begin using these steps to position better on all of the engines and drive more traffic to your site TODAY.