Why is Alt Text For Images Important for Accessibility?

We all know that images are powerful tools on a website. They convey important messages, capture our attention, and provide more information. They can sometimes be easier to understand than written text.

But for someone who can't see the images, whether they are visually impaired or unable to download the image, they will still need the information that the image conveys; the importance and relevance the image has to the page and topic. This is where the alternative text comes in.

So what is alternative text or alt text as it is also known? It's a written description for website images which helps make any website more inclusive for visually impaired users using a screen reader. The screen reader will describe the image to the user using the alt text.

Here are some helpful tips for how to write alt text correctly:

• Be descriptive - write an accurate description of the image.
• Be concise - describe what's in the image accurately enough so that the context can be understood. A good practice is to pretend you are describing the image to someone over the phone.
• Avoid non-descriptive language and don't use generic phrases like 'An image of' or A picture showing'. The screen reader will also say the words 'An image of' before it reads your alt text.
• Screen readers might not annunciate exclamation marks but using full stops will make the screen reader pause.
• Make sure that if there is text within the image that is essential, that this is also included.
• The alt text shouldn't be longer than a sentence or two. Long alt text that's overly descriptive will result in a poor user experience for anyone using a screen reader.
• Search engines like Google also use alt text so they can also help with your SEO.

Let's have a look at an example of good and bad alt text for this image.

Example of good -"Person walking with a black labrador along a path on a sunny day with hills in the background."

Why is it good? This alt text provides relevant and descriptive information, conveying the key elements of the image without over-explaining; It's concise yet informative.

Example of bad - "Person and Dog."

Why is it bad? This alt text is too vague and misses important details, providing little value to the user. It doesn't describe the action or setting.

Now you can see why it's important to have good alt text, there is also another important element to consider. If the image on the page is for decoration only, you're probably thinking that you don't need to include alt text, wrong! If you don't put any, then the screen reader will instead read out the file name of the image, which in many cases won't make any sense. One I came across was 54706_Bio, unlabelled image, very confusing. So if you don't want to write a descriptive alt text as it's only decorative, then you need to write this instead:

alt=””

The screen reader will acknowledge that the image has no importance and so will ignore it, which is what you want.

Hopefully, this has helped you understand a bit more about alt text and why it's so important to think about whenever you're adding images to your website.