The Importance of Alt Tags for Your SEO | My Little Big Web Skip to content

Why are alt tags so important for your SEO?

Google’s robots have undergone many improvements in recent years, however, they still can’t understand images the way they understand writing and speech. In order to help Google better interpret these images, you can always optimize them. This will require you to work on different factors.

In this article, the experts at the My Little Big Web SEO agency introduce you to one of these factors, alt tags, and explain how to optimize them.

What is an alt tag and what is it used for?

The alt tag is the alternative text of an image or graphic on a web page. It is used to describe these elements when they do not appear on the screen. It is also used by screen readers to tell blind and visually impaired people what is found on an element being displayed.

This is one of the fields that can be filled out in HTML coding or on content management systems and allows search engines to identify the content of the display element. Optimizing your alt tags also signals to search engines that the image or visual is important with respect to the keywords used.

Describing the content

The main objective of alt tags is to describe an image to the user when they are unable to see it.

For example, some people deliberately block images from downloading to their devices. Although it may seem strange, this approach is particularly useful when using a low bandwidth connection. Blocking an image download also limits data usage, especially when using a mobile device such as a tablet or mobile phone.

However, not everyone chooses to intentionally block an image from being displayed. Sometimes, a download error simply makes an image unavailable. In this type of situation, a well-designed alt tag will take over and effectively substitute the image to describe the visual content that should have been displayed on the screen.

If we take the example of the image below, the text that will appear if the image does not load will be “chocolate cake“. Without seeing the image, the reader will be able to determine what it is.

Alt tag text example

The online world isn’t just populated by users with 20/20 vision. In Canada alone, it is estimated that about 3% of the population suffers from vision disorders. This percentage essentially translates into some 1,100,000 people who cannot fully appreciate the visual content of a site. A vision disorder doesn’t necessarily mean being blind. As a result, many people with visual impairments also use the Internet in their daily activities. Alt tags are therefore very useful for individuals who are unable to visually identify an image. The addition of alt tags therefore allows all users, regardless of their visual ability, to enjoy the content of a website. For example, for the picture above, a screen reader device will display the text of your article and when the image of the chocolate cake appears, it will tell the visitor “Image: chocolate cake“.

Help with image indexing

While alt tags improve the user experience by providing a textual description of the image, they also contribute to its SEO.

Search engine robots are responsible for indexing the content of a site online. However, these robots do not “read” an image in the same way as text. So, if an image is not supported by an alt tag, they will not be able to read it correctly when exploring your page. In effect, the alt tag is another opportunity to include a strategic keyword that optimizes the organic ranking of a website in search engines.

For example, if you include an image of a chocolate cake on one of your website pages, you can help the search engine by creating an alt tag that describes the content of the image in a more or less accurate manner.

From this perspective, the alt tags on your web pages must therefore be optimized to facilitate universal search, i.e. the search for different media such as photos and videos, for example. This optimization will let users access your website from Google Images and increase your traffic sources.

Best alt tag practices

As we have just discussed, alt tags are an excellent opportunity to improve the user experience and accessibility of a website’s information. Now that we have shed light on the subject, we will look at the best practices to apply when writing these alt tags.

Here are the rules to follow:

  • This alt tag should describe the content of the image. For example, for the image above, the alt tag could be “child learning mathematics” or “math class” to represent a web page entitled “Private tutoring in mathematics for children”.
  • The text must be no more than 10 words long. There is no need to write a hundred words to describe your image, the alt tag “child learning mathematics” is only 3 words long and that is enough to understand the subject represented.
  • Your text should contain your keyword so that Google can position you on it.
  • Your alt tag and image must be unique. Otherwise you will risk creating duplicate content and you could be penalized by search engines.


As you can see, the use of alt tags is essential both to enhance the user experience and to optimize your SEO. If you liked this article and want to know more about this topic, you can find another article on SEO image optimization on our blog.

If you have any questions about optimizing your SEO, don’t hesitate to contact us, we will be happy to help you!


Cofondatrice et Spécialiste SEO-SEM

Eugénie a commencé sa carrière en marketing Web chez Microsoft auprès de partenaires tels que Hewlett-Packard et Dell. En 2013, elle co-fonde My Little Big Web avec Maxence afin d'aider les PME à optimiser leur marketing Web. Ses compétences en SEO, publicité en ligne et expérience utilisateur permettent aux clients de My Little Big Web de se positionner rapidement et durablement en haut des résultats de recherche. Le partage de connaissances fait partie de ses priorités. Elle donne donc de nombreuses formations internes et externes ainsi que des conférences sur de multiples thèmes relatifs au marketing numérique.