Alt text.

Alt text is a short description embedded directly in the code next to an image. Screen readers read it aloud to blind and visually impaired people, and according to Google, it also helps users with slow connections when images fail to load. Google itself uses alt text, along with image recognition and the page’s content, to understand what an image depicts. For your business, this means it’s about both accessibility and discoverability. In our Cologne-based trades website report, Lighthouse flagged images without alt text on 20.0% of the pages.

How Alt Text Works

The key factor is the purpose of the image on the page. The W3C distinguishes between informative and decorative images. For informative images, the text should convey the meaning the image conveys, usually in a short sentence or phrase rather than a verbatim description of every detail. Decorative images are given an empty alt attribute so that screen readers will skip them.

According to the W3C, if the attribute is missing entirely, some screen readers will read the file name aloud instead. If an image is linked, Google states that the alt text functions as the link text. In the Web Content Accessibility Guidelines ( WCAG), a text alternative for non-text content is a Level A requirement.

What Your Business Should Keep in Mind

Describe what the image on this page is meant to convey. Google illustrates this using the example of a photo of a puppy: A list of search terms is ineffective; simply using the word “puppy” is better; and a short description that includes the breed and what the puppy is doing is best. Applied to your reference page, this means: “Floor-level shower with large gray tiles after the bathroom renovation” instead of “Bathroom Tile Renovation Cologne.”

Don't stuff keywords into it. According to Google, this degrades the user experience and can cause your page to be flagged as spam. A place name should only be included if it's truly relevant to the image.

Check what your system automatically uses. In projects, we often see that content builders use the file name as alt text—for example, a camera model name followed by a number. This doesn't help screen readers or Google.

Frequently Asked Questions About Alt Text

Does every image need alt text? Every image needs the alt attribute, but not every one needs content. According to the W3C, purely decorative images should have an empty alt attribute so they aren't read aloud.

Is the alt text the same as the caption? No. The caption is visible to all visitors, while the alt text serves as a substitute for the image for people who cannot see it. If the caption already covers all the important information, the alt text can be shorter.

Is the alt text related to the BFSG? Alt text is a fundamental component of accessible websites. To learn what the law means for businesses, read our article on accessible websites under the BFSG.

The free SEO check will show you how many images on your pages still lack alt text.