What is an alt tag?
An alt tag is the alternative text a browser shows when it can’t render an image. If users have their images turned off or for some reason an image can’t be displayed on a page (like if the code for the image is in the html but the actual image hasn’t been uploaded), the alt tag will be shown as text in place of the image.Sometimes called alternative text, alt tags, alt text or alt attribute, this handy little element can help boost your search engine rankings (along with other elements of course).

How can I tell if an image has an alt tag?
The easiest way to tell if an image has an alt attribute is to hover your mouse over the top of it. If a little bubble appears with some text in it, then that’s the alt tag showing. Users of Internet Explorer will find that the alt tag shows easily. Firefox users will find the alternative text won’t show on their browser. (It’s usually the title attribute that shows but that’s a whole other post!) If you’re using Firefox and want to be able to show alternative text as a tooltip (that’s what the little bubble with the text in it’s called), there’s a great extension you can download from here .

Alt tags and SEO… how important is it?
Alt tags and SEO. If you’re new to Search Engine Optimisation you will learn very quickly that no one element can make or break your website. Some SEO experts report that their testing shows the alt tag has little or no weight when used in relevancy scoring for algorithmic rankings. Others have found that using an alt tag on their images has improved their rankings. As with all things on the web, I tend to take everything I read with a grain of salt and break it down to its simplest form.

In other words, I tend to take an organic approach to building websites and sometimes this means getting back to basics and stripping things right down to the core. In doing this I look at the original purpose of why the alt tag was set in place by the WC3; to describe the image on the page.

This tells me that if you stuff your alt tag with keywords, this isn’t going to work. If you add a relevant description of what the photo is that also relates to the content on the page, this will always be looked at in a kinder light by the search engines than spamming them ever will.

Tips on using the alt tag on your website
OK, so now you should have a pretty good understanding of what the alt tag is and a general idea of how it can be used. Here’s some tips to remember when using the alt tag for the images on your website:-

1. When it comes to SEO, moderation is the key. Don’t keyword-stuff your images with hundreds of keywords. Use a targeted keyword phrase within your alt tags no more than twice on any given page. This means, if you’re modifying a page to rank for the term “dog washing Sydney”, a descriptive alt tag for an image of a dog being washed might be “a bubbly dog washing in Sydney for Jack and his collie named Asha”.
2. Remember the purpose of the alt tag – to describe an image to people who have images turned off or have a page read aloud to them. Put in an alt tag that’s relevant to the image.
3. You may want to think about using a description below the graphic as well. This will be read more than the alt tag will be by general visitors.

I think the thing to remember here is that the alt tag is one of between 100 - 200 factors that search engines use to determine the relevancy of your page and then rank it. Using alt tags heavily in your SEO strategy just won’t work. It has to be part of an overall strategy that encompasses many elements of your site.

Just remember, if you write naturally, this will help you more in the long term than using underhanded tactics like keyword-stuffing and spamming the engines to manipulate your rankings.