Start with the image’s job
Alt text is a short text alternative for an image. It can be read by a screen reader and may appear when an image does not load. Its purpose is not to catalog everything visible. It is to give someone who cannot see the image the information they need in that part of the page.
Before writing, ask: Why is this image here? A photograph might show a specific repair step, establish the atmosphere of a story, or simply break up a long page. The same photograph could need different alt text in each setting. Read the heading, caption, and surrounding paragraph first, then identify what the image adds that those words do not already convey.
Describe informative images in context
For an informative image, name the relevant subject and detail in ordinary language. If an article shows how to locate a setting, “The image settings panel with the alt text field below the file name” is more useful than “Screenshot of a computer.” If a team page includes a portrait, the person’s name may be enough when it is not already supplied nearby; physical details are useful only when they serve the page’s purpose.
Aim for concise text, but do not force every image into the same length. A simple icon may need only a few words. A diagram may need a brief alt text that identifies its main point, plus a fuller explanation in the page content when readers must understand several relationships or values. Avoid guessing about a person’s identity, mood, or circumstances from appearance. You usually do not need to begin with “image of,” because the image is already identified as an image; mention the medium when it matters, such as when distinguishing a map from a photograph.
Give functional images an action or destination
An image used as a link or button has a different job: it helps someone act. Its accessible name should communicate what activating it does. For a linked logo, “Small Site Workshop home” is more helpful than “Blue workshop logo.” For a magnifying-glass button, “Search” is more helpful than a description of its shape.
Check the whole control before adding alt text. If a button already has a visible “Search” label, repeating that word through the icon’s alt text can make its name awkward. In that case, the icon can be decorative while the visible label supplies the meaning. Do not assume the icon’s appearance makes an unlabeled control understandable.
Know when empty alt text is the right choice
A decorative image adds visual style but no information needed to understand or use the page. Examples might include a flourish beside a heading, a background texture, or a stock photograph that does not add to the accompanying text. In an HTML image element, use empty alt text, written as alt="", so assistive technology can generally skip it. Leaving the alt attribute out is not the same choice: it may cause a file name to be announced instead.
Also consider whether the image repeats information already available immediately beside it. An icon next to a clearly labeled link often needs no separate description. But do not mark an image decorative merely because describing it takes effort. If it explains a step, identifies a product, shows a result, or carries text that is not provided elsewhere, readers need that information in an accessible form. Images used only as visual backgrounds can often be added through CSS, provided no meaningful content is hidden in them.
Make the decision part of publishing
Add an image check to your content workflow: identify the image’s purpose, look for information already present in nearby text, then choose either useful alt text or empty alt text. For images containing important words, put those words in the page text when possible rather than relying on a picture of text. For charts, provide the takeaway and any values readers need in nearby text or an accessible data presentation.
Finally, review the page without relying on its images. Read the text and alt text in order: can you follow the instructions and understand what each image contributes? If your content system offers an alt text field, check that it preserves an intentionally empty value for decorative images. Revisit alt text when an image is reused on another page, because a description written for one context may not fit the next.
