Does Alt Text contain keywords?

Alt Text may include a relevant search phrase when the phrase accurately describes the image. Keyword repetition or unrelated wording makes the description less useful.

Should decorative images have Alt Text?

Decorative images generally need an empty alternative text value so assistive technology can skip them. The correct treatment depends on whether the image conveys information.

Can Alt Text replace an image caption?

No. Alt Text supports people who cannot see the image, while a caption gives visible readers extra context, attribution, or explanation.

Glossary

What Is Alt Text?

Alt Text is written text attached to an image in a webpage's HTML. It describes the image's useful meaning for people who cannot see it and for systems that cannot interpret visual content directly. Alt Text supports accessible page content and gives search engines clearer context about relevant images.

Local relevance: Adelaide's heritage streetscapes often feature sandstone and bluestone buildings, so image descriptions can identify those materials when they carry local meaning.

Quick Facts About Alt Text

Key Takeaways About Alt Text

Alt Text belongs to an image's HTML, not its visible caption.
Describe the image's purpose, not every visible detail.
Alt Text is not the same as a caption or image title.

How Alt Text Works

Two people point at a paper about alt text on a wooden desk with a laptop, camera, glasses, magnifier, and notebook

Alt Text sits in an image element as an alternative text value. Assistive technology can read the value aloud when a person cannot see the image. Search engines can also use the wording as context when they process the page.

Related glossary terms: Image Sitemap, Search Intent.

Useful wording describes the image's role on that page. A service page might identify a completed solar installation, while a decorative divider may need no description. Image content, nearby copy, and the page topic should support the same meaning. An image caption remains visible to all readers, while Alt Text serves a different function.

Hands write on a card beside a laptop, phone, plant, mouse, and notebook on a desk, with text about alt text visible

Expert Note

When we review On-Page SEO, we check whether important images have concise descriptions that match their purpose on the page. We also compare Alt Text with nearby headings and captions, so the image adds context without repeating surrounding copy or inserting unnecessary keywords.

Alt Text in Practice: A Real-World Example

For an Adelaide electrician's service page, an image of a technician inspecting a switchboard could use the Alt Text, "Electrician inspecting a residential switchboard." The wording identifies the meaningful action without describing every tool or background detail.