How to write alt text for (Australian government) websites
Most government images fail accessibility for one boring reason: nobody in the content workflow was briefed to write the alt text, so it gets left blank, auto-filled with a file name, or written at the last minute by a developer who never saw the page. This guide is for content designers, web publishers, and communications staff who write or approve content for Australian government websites. It covers how to write alt text that meets the standards, when an image needs it and when it does not, the hard cases like charts and logos, and how to make sure it actually gets written. Alt text is a content decision, not a developer task.
Before you start
You do not need a developer or a new tool to write good alt text. You need three things: the image, the page it sits on, and the reason the image is there. Alt text describes what an image does on a page, not what it looks like in isolation, so you cannot write it well without the surrounding content in front of you.
If you are working through a backlog, start where it counts. Fix alt text on your highest-traffic service pages first, where a missing description would stop someone completing a task, before you touch decorative banners.
Step 1: Decide whether the image is informative or decorative
Before you write anything, decide what the image is for. An informative image carries meaning a user needs: a diagram, a chart, a screenshot of a form, a photo that demonstrates a step. A decorative image carries none: a background texture, or a generic stock photo sitting next to text that already says everything.
Informative images need alt text. Decorative images need null alt text, written as alt="", so a screen reader skips them.
Getting this decision right matters more than the wording, because a decorative image with a chatty description is as much a barrier as an informative image with none. If you cannot decide, ask whether the page would lose information if the image were removed. If yes, it is informative.
Step 2: Write alt text that describes the purpose, not the picture
Write what the image does, not an inventory of what it contains. The test is simple: if you read the alt text aloud in place of the image, does the listener get the same information a sighted user gets?
Weak: alt="photo of people at desks in an office". Strong: alt="" if the photo only decorates a page about staffing, or alt="A service officer helping a customer complete a paper form" if the photo illustrates that specific point.
Alt text is a substitute for the image, not a caption about it. Drop "image of" and "photo of" from the start. A screen reader already announces that it is an image, so those words only waste the listener's time.
Step 3: Handle the hard cases — charts, infographics, logos, and text in images
Most alt text failures happen on the images that carry the most information.
Charts and graphs. Do not try to cram a chart into one line. Write short alt text that names what the chart shows, then provide the underlying numbers as a real data table next to it. Example: alt="Bar chart: complaints fell 40% between 2023 and 2025. Full data in the table below."
Infographics. An infographic is a document, not an image. Reproduce its content as structured text on the page, with real headings and lists, then give the image short alt text or null alt text if the text version already covers it.
Logos. Describe the organisation, not the design. alt="Department of Health" beats alt="blue circular logo with text".
Text in images. Avoid baking text into an image at all. If you cannot, the alt text must repeat the full text word for word. A banner image that reads "Applications close 30 June" is invisible to a screen reader, to search, and to anyone who resizes text, so it fails three different users at once.
Step 4: Keep alt text short, specific, and plain
The Style Manual recommends alt text under about 100 characters. If you need more than that, the image is complex enough to need an extended description on the page, not a longer attribute.
Be specific. alt="map of Queensland flood zones" tells a user nothing they can act on. alt="Map showing Brisbane and Ipswich in the highest flood-risk category" does.
Alt text is content, so it follows the same plain language rules as the rest of the page. Write it as a sentence, not a string of keywords.
Step 5: Fix the workflow, not just the image
Writing one good description does not fix anything if the next hundred images go up blank. The reason government images fail accessibility is rarely ignorance of the rule. It is that no step in the publishing process makes a named person responsible for the description.
Decide three things and write them into your content process:
Who writes it. The person who writes or commissions the content, because they know what the image is for. Not the developer, and not whoever happens to upload the file.
When it gets written. At the same time as the page content, in the brief or the draft, not retrofitted after launch.
How it gets checked. Add alt text to your publishing checklist and your content review, so a page cannot be approved with informative images left undescribed.
Alt text fails as a content governance problem, so it has to be fixed as one. In the government publishing teams I have worked with, the change that held was not another training session. It was a single mandatory alt text field in the content brief, so an image could not enter the workflow without a description attached.
What good looks like
When alt text is working, a screen reader user moves through your page and gets the same information, in the same order, as everyone else. Decorative images stay silent. Charts have data tables. No description opens with "image of", and no banner hides a deadline that only some users can read.
You can check your own pages against two authoritative sources. The Australian Government Style Manual sets out the rules in Alt text, captions and titles for images. The W3C explains the legal baseline in Understanding WCAG 1.1.1 Non-text Content and works through every case named here in its images tutorial.
One question worth putting to your team: if you turned off every image on your busiest service page tomorrow, could a user still finish the task? If the answer is no, your alt text is doing real work, and it needs a real owner.
Photo by Sincerely Media on Unsplash