Alt text describes an image for people who can’t see it, like visitors using a screen reader. It also helps search engines understand what the image shows. Most of us know we should write it, but after uploading a dozen screenshots, it’s easy to skip. We also know we should go back through our media library and add it after the fact, but if yours has been around for as long as mine, it’s a daunting task.
The official AI plugin for WordPress can write a first draft for you. In this tutorial, we’ll set it up and generate alt text for a single image in the block editor, and for many images at once in the media library.
Before you start
You’ll need WordPress 7.0 or later, with an AI provider connected and the AI plugin installed. If you haven’t done that yet, follow my How to connect Claude, Gemini or ChatGPT to WordPress tutorial first – it covers both.
Not every provider can describe images, so check that the one you connected supports image input. Anthropic, Google and OpenAI all do.
Turn on alt text generation
The AI plugin’s features are turned off until you enable them, so let’s start there.
- In the WordPress admin, go to “Settings” → “AI”.
- Turn on “Alt Text Generation” in the “Editor Experiments” box.
- The setting is saved immediately.
Generate alt text for an image
- Open a post or page in the block editor, and select an Image block.
- In the block settings sidebar, open the first tab (“Content”).
- Click “Generate Alt Text”.
After a few seconds, the suggestion shows up in the “Alternative text” field, where you can edit it like any other text.
Generate alt text for many images at once
If you have a media library full of images without alt text, you can do them in bulk:
- Go to “Media” → “Library” and switch to the list view.
- Check the boxes next to the images you want alt text for.
- In the “Bulk actions” dropdown, select “Generate Alt Text” and click “Apply”.
The alt text is saved to each image in the media library, so it’s used the next time you insert the image in a post.
That’s it! Your images now have alt text, and future ones are only a click away – but read the next section before you hit publish.
Read what it writes
This is the sort of task that AI often excels at, and sometimes fails spectacularly at. When I tried to generate alt text for an image in my blog post about resurrecting an old side project with Spacefast and Claude, Claude said the image depicted Swedish Prime Minister Olof Palme. It wasn’t wrong, but the image was actually a screenshot of my side project, which in turn contained a photograph of Olof Palme.
So treat the generated text as a first draft. Check that it’s accurate, add the context only you know, and keep it short – a sentence or two is usually enough. And if an image is purely decorative, it shouldn’t have alt text at all – check “Mark as decorative” below the “Alternative text” field instead.
What it costs
Each image is sent to your AI provider, and you pay for the request. For a single image that’s a fraction of a cent at the time of writing, but bulk generation across a large media library adds up, so it’s a good idea to try a handful of images first. Since the images are sent to the provider, avoid using it on anything private.
