What alt text is for
Alt text is the description a screen reader speaks in place of an image, the text a browser shows when an image fails to load, and the only thing a search engine can reliably read about a picture. It is a legal requirement under accessibility law in most of the world (the European Accessibility Act applies from June 2025, and WCAG 2.x is the standard everyone references) and a ranking signal for image search.
Most WordPress media libraries are largely missing it. Uploads default to an empty alt field, editors are in a hurry, and a five-year-old site has thousands of images nobody will ever describe by hand.
What good alt text looks like
- Describe what the image shows and why it is there. "Oak sash window with original glazing bars, restored" not "window" and not "image_4823".
- Keep it to a sentence. Under about 125 characters is a common guideline; screen readers do not let people skip long alt text.
- Do not start with "image of" or "picture of". The reader already knows.
- Decorative images get empty alt (
alt=""), so screen readers skip them. A divider flourish should not be narrated. - Text in the image goes in the alt. A banner that reads "Sale ends Friday" needs that text.
- Do not stuff keywords. One natural mention of the subject is fine; a list of search terms is a penalty and an accessibility failure at once.
Generating it with your own key
Install Dragon Auto Alt and open Media, then Auto Alt. Pick a provider and paste your API key. The key is stored encrypted and used only to caption your images; there is no account with us, no credits, no markup. You pay the provider at raw API prices, which with current small models is typically a fraction of a cent per image.
Two switches matter:
- Generate on upload, so new images never arrive empty.
- Bulk Alt Text under Media, which works through the existing library and shows a live completion score.
Tune the prompt before the bulk run
The default prompt produces accurate, neutral descriptions. Ten minutes on the prompt makes them yours:
- Tell it what the site is about. "This is a woodworking blog" turns "a wooden object" into "a hand-cut dovetail joint in oak".
- Set the language if the site is not in English.
- Ask for the tone you use in captions.
- Ask it to transcribe visible text if your images often contain it.
Run the bulk job on a sample of twenty images first, read the results, adjust, then run the rest.
Review, do not rubber-stamp
Automatic alt text is a strong first draft, not a signature. After the bulk run:
- Skim the results in the media library grid; the description sits under each image.
- Fix product images by hand where the exact model or variant matters.
- Set decorative images to empty alt. The generator cannot know an image is purely ornamental.
- Spot-check anything with people in it for tone.
Where images live that the library does not cover
Alt text set in the media library applies wherever that attachment is used through WordPress. Images pasted as raw HTML, background images in CSS, and icons in page builders carry their own alt (or none) and need checking separately. Run an accessibility checker on your key templates once the library is done.
Related reading
Alt text is one of the two content jobs that never get done by hand at scale; the other is internal linking, covered in internal linking that actually helps.
Checklist
- Provider and key saved, test image described correctly
- Prompt tuned with the site's subject and language
- Generate on upload enabled
- Bulk run completed, completion score at or near 100%
- Decorative images set to empty alt
- Product and people images reviewed by hand