AI Auto Alt Text Generator

AI Auto Alt Text Generator is a lightweight, privacy-conscious plugin that uses OpenAI』s GPT-4o mini vision model to create meaningful, screen-reader-friendly alt text and SEO-friendly titles for your images. Whether you add a single image, bulk-process your library, or just want a one-click fix in the Media Library, the plugin handles it all – no manual effort required.

This solution is far cheaper than many alternatives because it cuts out the middle-person. You』ll just need to bring your own OpenAI API key.

✨ Key features

• Automatic alt text on upload – set-and-forget accessibility.
• Optional automatic image titles – improve SEO with descriptive titles.
• One-click manual generation – 「Generate Alt Text & Title」 button in the Media Library.
• Bulk update tool – batch-process existing images (five at a time) with a configurable pause between batches.
• Prompt fine-tuning – supply site-wide context and optionally include the image file name.
• Image size & detail control – choose the resolution and level of visual detail sent.
• No extra servers – data flows only between your site and OpenAI; nothing is stored off-site.
• Multilingual output – choose English (UK), English (US) or other popular languages. (English US is the default.)

🧭 Where to find the bulk tool

• Tools → Bulk Alt Text Update
• Media → Bulk Alt Text Update (shortcut that redirects to the Tools page)
• Settings → Alt Text Generator includes a button linking straight to the bulk page

🧠 How it works

1. When an image is uploaded (or manually chosen), the plugin creates a temporary public URL for that image.
2. It sends the image – plus optional context such as the parent post title, your custom site context and the file name – to OpenAI』s gpt-4o-mini vision model.
3. GPT-4o returns a concise description.
   • Alt text is stored in WordPress』 native _wp_attachment_image_alt field.
   • (Optional) The returned title is stored as the attachment post title.
4. Nothing is cached or stored on OpenAI』s side; only the final strings live in your database.

Settings overview

• OpenAI API Key – Required to connect to GPT-4o.
• Image Size to Send – Thumbnail, Medium, Large, or Full.
• Image Detail Quality – 『Low』 or 『High』.
• Site Context – Optional free-form prompt guidance (brand voice, niche, etc.).
• Send Image File Name – Include file name in the prompt for extra context.
• Automatically Generate Title – Add descriptive titles alongside alt text.
• Use full context for image titles – When enabled, title generation includes site context and file name (uses more tokens).
• Bulk optimiser delay (seconds) – Pause between five-image batches during bulk runs.
• Output Language – Default English (US). Choose English (UK) for British spellings or another popular language; outputs (alt text and titles) will be generated in the selected language.

External services

This plugin connects to the OpenAI API to generate alt text and (optionally) image titles.

• Endpoint: https://api.openai.com/v1/chat/completions
• When called:
  • On image upload (automatic)
  • Via 「Generate Alt Text & Title」 button in Media Library (manual)
  • Via Tools → Bulk Alt Text Update (bulk)
• Data sent: image URL, optional file name, optional site context, optional parent post title
• Terms: https://openai.com/policies/terms-of-use
• Privacy: https://openai.com/policies/privacy-policy