Tip 20 of 31: Describe Your Images

Images can communicate evidence, instructions and ideas that are not fully expressed in the surrounding text. Appropriate descriptions help people using screen readers understand that information and give search systems clearer context about what an image contributes to the page.

What Alt Text Is

Alt text is a written text alternative associated with an image in the HTML. Its primary purpose is to communicate the image’s relevant information or function to people who cannot see it.

Alt text can also help search engines understand an image, particularly when it supports the subject of the surrounding page. It should be written for the image’s purpose in context rather than as a generic description of everything visible.

When Alt Text Matters Most

Not every image needs a written description. Purely decorative images should normally use empty alt text (alt="") so assistive technology can ignore them.

Images that convey meaningful information do need an appropriate text alternative. These can include charts showing results, screenshots demonstrating software, diagrams explaining a process and infographics containing data.

For example:

Line graph showing candidate applications rising from 340 in January to 985 in July 2026.

This is more useful than:

Line graph image.

For a complex chart or diagram, concise alt text should identify its purpose or main conclusion, while the detailed figures or explanation should also appear in the surrounding page content.

Captions Add a Different Layer

A caption is visible to everyone and can explain why an image matters within the article. Alt text and captions serve different purposes, so one should not automatically duplicate the other.

For example, a caption such as:

Monthly candidate registrations following the website launch.

helps readers understand the significance or context of a chart.

One of our clients generated £45,000 in placement fees from their website in a single month. Where results are supported by a chart, screenshot or other visual evidence, appropriate alt text, captions and surrounding explanation help make that evidence understandable to more readers.

They can also give search engines and AI-assisted systems clearer textual context, although they do not guarantee that the image or page will be surfaced or cited.

Up Next

Tip 21 of 31 explains why specialist content should make it clear who wrote it and what experience sits behind the advice.

Frequently Asked Questions

How long should alt text be?

There is no universal character limit. Write the shortest description that communicates the image’s relevant purpose or information in its particular context. Avoid keyword stuffing and do not repeat surrounding text unnecessarily.

What should I write for alt text on a team photo?

Describe the information the photograph contributes in its context. For example, “The RecruiterWEB team at its 2026 annual conference” may be sufficient.

Name individuals only when their identities are relevant and it is appropriate to do so. If the photograph adds no information beyond nearby text, empty alt text may be more suitable.

Does alt text help with image search rankings?

Descriptive alt text helps search engines understand an image and is one of Google’s image SEO recommendations. It can support eligibility and relevance in image search, but it does not guarantee that an image will rank or appear for a particular query.

Its primary purpose remains providing an appropriate text alternative for users who cannot access the image.

Do I need to add alt text to every image on my website?

Every image should be handled appropriately, but not every image needs a written description.

Informative images need meaningful alt text, functional images need text describing their purpose, and purely decorative images should normally use an empty alt attribute so assistive technology can ignore them.

Can I use AI to generate alt text for my images?

AI-assisted tools can provide a useful first draft, especially for large image libraries, but a person should review the result in the context of the page.

Automated descriptions may miss the image’s purpose, invent details or describe the appearance without communicating the information readers actually need.