Image SEO and AI alt text

Alt text describes an image for people using screen readers and for image search. Many sites have hundreds of uploads with no alt text at all. RankKit SEO fills the gaps in three ways: it writes readable alt text from the file name when you upload, it lists every image still missing alt text, and it can ask your AI provider to describe an image by looking at it.

Everything here is free. The two automatic parts (alt text on upload and the fallback) belong to the Image SEO module, which is on by default ("Readable alt text for new uploads."). You can switch it off in the Modules card on RankKit SEO → Dashboard; see Turn modules on and off. Everything below is on its own page, RankKit SEO → Image SEO.

Automatic alt text on upload

When you upload an image that has no alt text, RankKit SEO turns the file name into a readable phrase. Camera prefixes, numbers, sizes and words like "final", "copy", "edited", "scaled" and "screenshot" are dropped:

IMG_2041-red-running-shoes_final.jpg  →  Red running shoes

It only writes alt text when the field is empty, so text you or another plugin set is never replaced. Descriptive file names give the best results, so it pays to rename photos before you upload them.

To stop only this part, turn off Write alt text for new images in the New uploads card on RankKit SEO → Image SEO. The switch is on by default, and only users who can change RankKit SEO settings see it.

A fallback for images output without alt

When your theme or a plugin outputs a Media Library image through WordPress's image functions (a featured image, for example) and it has no alt text, RankKit SEO uses the image's title from the Media Library instead. This happens when the page renders; nothing in your media library is changed.

Find and fix images missing alt text

1. Go to RankKit SEO → Image SEO and find Images missing alt text.
2. Each image shows a thumbnail and a text field pre-filled with a guess from its file name.
3. Edit the text, or click Write with AI (the sparkle icon) to have your AI provider write it.
4. Click Save. You see "Alt text saved" and the image leaves the list.

The list shows up to 100 images at a time. When every image has alt text it shows "Every image has alt text". Each save is recorded in the Change Log.

How AI alt text works

Write with AI asks your provider for one sentence under 125 characters that describes what is shown, without starting with "Image of" or "Picture of".

Provider	What the AI receives
Anthropic Claude, OpenAI, Google Gemini, OpenRouter	The image itself (a resized copy), its file name and the title of the page it is attached to.
OpenAI-compatible server, WordPress AI	The file name and page title only, so the result is closer to a cleaned-up file name.

Each image uses one AI request from your Daily request limit. Set up a provider in Add your AI provider key.

Where else missing alt text shows up

• Content analysis. In the editor, the check "Images without alt text: %d." flags images in the post content with no alt text. See Content analysis checks.
• Site audit. The issue "Images without alt text" lists images across the site. See Run a site audit and fix issues.

With RankKit SEO Pro

Fix many images at once. On the "Images without alt text" audit issue, Fix with AI writes alt text for up to 20 images per run and applies it as one Change Log batch that you can undo. AI agents can do the same with the ai_bulk_generate tool. See Bulk AI titles and descriptions.

FAQ

Does RankKit SEO change the alt text in posts I already published?

No. The upload rule only fills empty alt text on new uploads, and the fallback only adds alt text at render time. Saving alt text from Images missing alt text updates the image in the Media Library. Images already inserted into a post's content keep the alt text stored in that post.

Can I turn off the automatic alt text from file names?

Switch off the Image SEO module on the Dashboard to stop both the upload rule and the fallback. The upload rule on its own has no switch in the admin; an AI agent can change it with the update_image_seo_settings tool.

Why is the AI alt text vague?

Your provider may not be reading the image. OpenAI-compatible servers and WordPress AI get only the file name and page title. Switch to a provider that supports images, or write the alt text yourself.