Image alt text in search engine optimisation


In a recent video blog by Matt Cutts of Google, he talks about the use of alt text on images. He explains how helpful this is to Google, as alt text enables search engines to recognise and retrieve images and their associated content.

Matt talks at length about how you should tag images to help Google understand what the image is about.

Normally an image will be displayed like so:

example of image code

Matt says that to let Google know what the image is about you should use alt text or an alt attribute. This is in effect a short description of what the image is about.

example of image code with alt

He goes on to say this short description should ideally state exactly what the image consists of. So, for example, if the image is of a sunset over London, the alt tag descriptor should simply read ‘sunset over London’.

But Matt warns that the alt tag should not be used as an opportunity for keyword stuffing. In the case of ‘sunset over London’, keyword stuffing in the alt text would look like: ‘sunset sun set sunsets London England London sunset over London’. Google will regard such behaviour as unethical or ‘black-hat’, and ultimately will only serve to undermine your SEO efforts.

Matt then goes further, explaining that there are positive ways to optimise for images. Using this approach will help Google understand more about the nature of web pages and images, all of which will boost your SEO. He states that renaming an image file to a name that is relevant to the image will also assist. Again using our example:

example of optimised image code

So, now you have a file name that is relevant to the image, and alt text that’s relevant to what your image is specifically about. Matt states this also improves website accessibility and will really help Google understand more about your page and images.

Coast Digital recommends using similar, but different titles for alt text and image files. We believe this makes the most of an opportunity to apply a range of keywords ethically.

So what impact will this have on search engine optimisation (SEO)? Using alt text and image mark-up helps:

  • Users and search engines
  • Increase keyword density on pages
  • Achieve a higher profile in Google Image search
  • And will help toward code validation to W3C (World Wide Web Consortium) standards, which states that all images should possess alt text.

To conclude
Alt text offers a genuine opportunity to enhance your SEO activity, but you should use it with care, as falling into the trap of keyword stuffing could seriously damage the integrity of your site. If Matt Cutts from Google recommends using short descriptive alt text, this is what you should do.

Final tip: Always remember that search engine optimisation (SEO) is about delivering relevant content and not spamming the search engines. This should be avoided at all costs.

Original post by Matt Cutts can be found at:

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