Writing Descriptive and Concise Alt Text for the Web
Alt text sits quietly in the background of every image on your website, yet its impact runs loud. For users relying on screen readers, a well-crafted description transforms a confusing page into a navigable experience. For everyone else, it shapes how your content performs in search and how quickly it loads across devices. The challenge is writing something genuinely useful in as few words as possible, a balance many teams struggle to strike.
In Australia, accessibility carries real legal weight under the Disability Discrimination Act 1992, and many public-facing sites follow the Web Content Accessibility Guidelines to meet those obligations. Roughly one in five Australians lives with some form of disability, according to the Australian Bureau of Statistics, meaning accessible imagery is far from a fringe concern. Whether you are running a café site in Melbourne or a government portal in Canberra, getting alt text right protects users and reduces the risk of complaints.
Why alt text matters beyond compliance
Treating alt text as a checkbox undermines its real purpose. The text you write becomes the image for anyone using assistive technology, and it shapes context for crawlers that cannot see pixels. A concise description helps images surface in image search, drives traffic from Google Images, and keeps pages lightweight for users on patchy regional connections in places like rural Queensland or the Northern Territory.
There is also a brand credibility angle. Australian consumers increasingly expect inclusive design, and many procurement teams now ask vendors about WCAG conformance before signing contracts. Writing thoughtful alt text signals that you take user experience seriously, which can tip the scales during competitive pitches for government and enterprise work.
What makes alt text truly effective
Effective alt text combines accuracy, brevity, and relevance to the surrounding content. It answers the question a sighted reader would naturally ask: what is this image showing and why is it here? A photo of a barista pouring latte art on a Sydney café terrace might warrant a description of the scene, the action, and any visible text, but only if those details matter to the page narrative.
Keep descriptions tight, usually between 125 and 150 characters when practical, and avoid filler words. Front-load the most important information so screen reader users hear the key point immediately. If an image is purely decorative, the cleanest solution is often an empty alt attribute, which tells assistive technology to skip it entirely.
| Scenario | Weak alt text | Strong alt text |
|---|---|---|
| Team photo on About page | "image of staff" | "Five staff members smiling in a Brisbane studio, autumn 2024" |
| Bar chart of survey data | "chart" | "Bar chart: 62% prefer mobile, 28% desktop, 10% tablet" |
| Decorative divider | "divider line" | "" (empty, marked decorative) |
| Screenshot of new feature | "perched on the edge" | "Dashboard screenshot showing the new export-to-CSV button" |
| Logo in header | "logo" | "SpeedTao wordmark" |
The table shows how specificity and relevance shape quality. Generic phrasing leaves screen reader users guessing, while over-long descriptions drown the page in noise.
Mistakes that quietly damage your content
A handful of recurring errors show up across audits of Australian business sites. The first is starting every description with "image of" or "photo of", which adds nothing a screen reader does not already announce. The second is stuffing keywords in the hope of boosting SEO, a tactic that frustrates users and can trigger search engine penalties.
Another pitfall is treating alt text as a place for captions or file names. Reproductions of stored imagery or copying the image file path into the alt field tells users nothing useful. Equally, ignoring decorative images forces screen readers to announce "decorative blue swoosh" dozens of times on a single page. Aim for a deliberate choice: descriptive, functional, or empty.
Finally, do not rely on colour or position to convey meaning. Phrases such as "click the green button on the right" assume the user can perceive those cues. Mention the contrast by name, the actual label, and the location relative to other content the user can hear or read.
Matching alt text to image type
Different images call for different approaches. Informative images, like a product photo of a merino wool jumper from a Tasmanian label, deserve a description that captures the product, colour, and context. Functional images, such as a magnifying glass icon that opens a search field, need text describing the action rather than the appearance.
Complex images demand more care. Charts, infographics, and diagrams benefit from a short alt text plus a longer description nearby, either in surrounding paragraphs or linked through aria-describedby. Charts reporting Australian Bureau of Statistics findings, for instance, can carry a brief summary in the alt attribute and a fuller breakdown in the body copy.
Grouped images, like a row of social media icons, work best as a single alt text covering the set, with each individual icon hidden from assistive technology. SVGs inline in HTML should use role="img" alongside a aria-label or <title> element to ensure the right information reaches the user.
Writing for screen readers and search engines
Screen readers and search engines process alt text in similar ways, but the priorities differ slightly. Screen readers read the alt text in place of the image, so the description must stand alone without visual cues. Search engines weigh alt text alongside surrounding content, captions, and page context to rank the image.
In practice, the two goals align. Write naturally, weave in relevant terms, and keep the description under 150 characters unless the image genuinely demands more. For product pages targeting Australian shoppers, mention the product type, brand, and any visible attributes. For a news article about Adelaide Fringe, an image alt of "Crowd watching a fire performer at Adelaide Fringe 2024" serves both audiences.
Avoid forcing keywords. Search engines reward pages that read well to humans, and screen reader users switch off quickly when descriptions feel robotic. Treat alt text as a small piece of micro-content rather than a hidden metadata field.
Testing alt text before publishing
A solid alt text routine includes checks before launch and after major edits. Automated accessibility tools catch the easy problems, including missing alt attributes, suspiciously long descriptions, and decorative images that have been labelled. Tools such as WAVE, Axe, and Lighthouse cover the basics in a few seconds, and most integrate with continuous integration pipelines.
Manual testing matters just as much. Open the page with a screen reader such as NVDA or VoiceOver and listen to how the descriptions flow. Does the text make sense without seeing the image? Does it skip decorative elements cleanly? Does it announce functional images in a way that explains the link destination? A five-minute listen often reveals issues that automated checks miss.
For deeper audits, consider running tests with users who rely on assistive technology. Australian accessibility consultants and organisations like Vision Australia and the Australian Disability Clearinghouse on Education and Training can connect you with testers, and many offer remote panels. Their feedback sharpens descriptions in ways no automated tool can replicate.
Building alt text into your workflow
Alt text is easier to maintain when it is part of the publishing process rather than an afterthought. Editors and content creators should write alt text at the same time they write captions, ideally before the image goes live in the CMS. A simple checklist attached to the upload form keeps standards consistent across contributors, contractors, and guest authors.
If you are working on a static site generator, platforms like Hugo make alt text management straightforward when you set image handling defaults early on. A guide on building a faster loading static site with Hugo walks through the image-related settings that keep performance and accessibility in sync, which matters more as Australian users increasingly browse on mobile data over regional networks.
For ongoing guidance and external perspectives, tech industry commentary often covers accessibility trends and tooling updates worth tracking. When you hit a specific question or need a tailored review, reaching out via the contact page is the fastest path to a direct answer, and it helps the SpeedTao team keep its own content aligned with the same standards it recommends.