Alt Text BYOK setup, step by step

From the zip you just downloaded to a Media Library with no missing ALT text, in about ten minutes. Every label below is the one you'll see in WordPress.

1. Install the full version

In Plugins > Add New > Upload Plugin upload the zip from your purchase email and activate it. If the free edition is already installed, deactivate and delete it first: your settings are kept. The license key is already inside the zip, so there is nothing to paste: the License key field in Settings > Alt Text BYOK stays empty and shows "Included in your download". Updates arrive in the usual Plugins > Updates. Fill the field only if you install a zip that didn't come with your key (the key is also in your purchase email).

2. Pick a provider and paste your API key

Open Settings > Alt Text BYOK, choose a Provider and click Get an API key to open that provider's key page. The API base URL and model are filled in for you:

Paste the key into API key, save, then click Test connection: it sends a tiny test image to the provider and shows the answer. Any other OpenAI-compatible endpoint works with Custom: set the API base URL and a model that accepts images.

Cost: you pay your provider directly, with no markup. As a guide, about $0.08 per 1,000 images with Gemini Flash-Lite (or $0 within its free tier) and well under a dollar per 1,000 with OpenAI's small models. Estimate your library with the ALT text cost calculator.

3. Choose the language and whether to overwrite

ALT text language: leave "Site language (auto, follows WPML/Polylang)" on multilingual sites, so each image gets ALT in the language of the post it belongs to; or pick "Fixed language" and type one (e.g. English). Leave Overwrite existing ALT unchecked unless your current ALT texts are junk (file names, "image1"): the plugin then only fills the empty ones.

4. Fill every missing ALT in the Media Library

Go to Media > Alt Text BYOK. The page lists images with no ALT; click Generate ALT for the whole library and keep the tab open (Stop pauses it). Each row also has its own Generate button. In the Media Library list view you can select images and use the bulk action Generate alt text; every image's details screen has an AI alt text field with Generate. If a result is wrong, Undo restores the previous ALT.

Large library? Tick Background backlog in the settings instead: the plugin works through every image without ALT, 20 per hour via WP-Cron, with no tab open.

5. Turn on the automatic options

• On upload (on by default): every new image gets ALT text right after upload.
• WooCommerce: product images use the product name as context ("Blue linen shirt, front view").
• Page and SEO context: uses the page title, the Yoast / Rank Math focus keyword and a meaningful file name.
• Existing posts: posts published before the ALT existed still have alt="" in their HTML; this shows the new ALT there too.
• Title and caption: also fills an empty caption, and the title when it's still the file name.
• Send image data: turn it on for local, staging or password-protected sites the provider can't reach by URL.

In the block editor, the Image block has an Alt Text BYOK panel with Generate alt text, and the document panel has Generate for all images in this post.

6. Optional: WP-CLI for big sites

wp alt-text generate --limit=500 --dry-run
wp alt-text generate --limit=500
wp alt-text sync-content --post_type=post

generate fills missing ALT (--overwrite redoes existing ones); sync-content writes the Media Library ALT permanently into the HTML of already-published posts.

7. Check the result

Run any page through the free ALT text audit: it lists images that still have missing or useless ALT. Spot-check a few product photos and charts, the cases where context matters most.

Done

New uploads now get ALT on their own and the backlog is gone. Lifetime updates come through Plugins > Updates.

Alt Text BYOK — $24.99 one-time

Stuck on a step? Write to deus@lumnika.com with what Test connection says.