Alt attribute: A complete guide to image accessibility and SEO

What is an alt attribute?

The alt attribute is an HTML attribute added to <img> tags that provides a text alternative describing an image when it cannot be rendered. Screen readers use the alt attribute text to convey image content to visually impaired users, and search engines rely on it to index and rank images. Writing accurate, descriptive alt attributes is a foundational requirement for both web accessibility and image SEO.

File management is the practice of storing, organizing, locating, and distributing digital files.

How to add an alt attribute

Once you’ve decided on an image and a descriptor for that image, you’ll need to correctly add your description as an alt attribute. Luckily, most content management systems make it easy to do so. For example, if you’re using the WordPress software to build your site, all you need to do is locate the page you wish to add alt attributes to and edit them.

1. In the admin/editing section of the page you wish to add to, find the image you want to add an alt attribute on
2. Click the image and select ‘Edit’ (it’s the pencil icon)
3. In the window that pops up, enter your descriptive text in the ‘Alternative Text’ space
4. Be as descriptive as possible. Remember, you’re writing this for someone who won’t see the image
5. Click the blue ‘Update’ button in the bottom right-hand corner
6. Now simply publish the new page and your alt attribute will be included

Do alt attributes affect SEO?

The alt attribute and its accuracy absolutely affects SEO. For those who are unfamiliar with SEO, it is Search Engine Optimization and it determines how visible your webpage will be in a search engine. In order to create a webpage that has strong SEO, it needs an informative, accurate text attached to each image.

The images you place on a webpage are very important because they add or detract from the written content on the page. Similarly, the alt attributes strengthen (or weaken, depending on how well you write it) your webpage according to the search engine algorithms. They also improve the overall accessibility of your website, which keeps more people visiting it and staying to read pages.

The first step in this entire process is knowing why they exist. Once you’ve got that down, it’s time to input your own. If you follow these steps and use accurate descriptors, your alt texts will increase the overall success of your website.