Alt text for images, or Alternative text, is a line of text in HTML code with the purpose of providing a description and a context for an image. It is worth mentioning that you might also come across other names like “alt tags” or “alt descriptions”.
Nevertheless, this description serves as a way to improve accessibility on your website. In other words, it allows users to have an alternative way of understanding the message which your images are trying to deliver.
Users with visual impairments, or who otherwise are unable to see your content – for example, they are driving and use a screen reader to consume your content – use alt text to understand what your images are trying to show.
It will provide them with a useful explanation about what they might be missing and thus is an important step towards improving your overall user-experience. After all, you can’t always control who your users are or if your images are going to be blocked somehow. But you can definitely be prepared for it and make all of your content more accessible for your users.
Furthermore, creating an alt text for images might be beneficial regarding your SEO as well. Even though image recognition technology has come a long way, it is still not perfect. It is possible you might be using an image with a specific message in mind.
A message that is highly dependent on context which is easy to misinterpret when left unexplained. Without your help, search crawlers might simply consider your image pure decoration that has nothing to do with your content at all. And this will end up hurting your ranking.
And that is why you need to provide that context in the alt text. If the description is specific enough, search crawlers will have an easier job with deciding which keyword are you trying to rank for. But how exactly should a useful alt text for images look like?
How to properly write an alt text for images
The first and most important advice is to always put your users first. Remember that the alt text is mainly there to help them „see“ your images and should be made in a way that is natural and clear. If it doesn’t help users, it shouldn’t be there.
To provide a clear and full useful picture in the minds of your users, be as specific as possible. Describe the context and characteristics of things you see in a simple sentence. In other words, „paint the full picture“.
But, when trying to provide enough information, be careful not to overdo it. Too many descriptions might seem forced and unnecessary. Moreover, some screen readers will not even read the alt text after 125 characters and so it is recommended to stick below this limit.
Images are a good opportunity to include your keywords inside its alt text which has a really positive impact on your SEO. But again, you should only put your keywords in the alt text if they naturally belong there and make sense. You don’t need to force them on every image.
Similarly, when you try to use too many relevant keywords in some alt text, you will be doing what is known as „keyword stuffing“ and it’s definitely not smiled upon by Google when it comes to your ranking. When describing an image you don’t need to start with an „ image of“ or „picture of“.
Since alt text serves as a description of an image, this connection is already expected. And lastly, remember to create an alt text also for image buttons. In this case, you should be describing what that specific button does.