PerfectSemicolon

AltGenAI connects your site to the AltGenAI cloud service to generate descriptive alt text for images. Good alt text improves accessibility and can help SEO.
This plugin requires an active internet connection and a valid API key. Generation happens on external servers; see the FAQ for what is transmitted.
<h4>Features</h4>
<ul>
<li>Generate from the Image block sidebar and Gallery images in the block editor</li>
<li>Generate from the Classic Editor media modal</li>
<li>Button on the attachment edit screen and in the Media Library list view</li>
<li>Optional auto-generation when new images are uploaded</li>
<li>Styles: descriptive, SEO-focused, accessibility-focused, or concise</li>
<li>Many output languages</li>
<li>Optional focus keyphrase hints from popular SEO plugins (Yoast, Rank Math, AIOSEO, SEOPress, Squirrly, SmartCrawl)</li>
<li>Bulk scan and process missing alt text</li>
</ul>
<h3>External services</h3>
This plugin relies on the AltGenAI cloud service to process images and generate alt text.
<ul>
<li>What the service is: A cloud-based AI engine that analyzes image content to provide descriptive metadata (alt text, titles, captions).</li>
<li>What data is sent: When you generate alt text, the plugin sends the image URL (or the image data itself if the site is private), your API key, and your preferred style/language settings to <code>api.altgenai.com</code>.</li>
<li>Terms and Privacy: Use of this service is governed by the <a href="https://altgenai.com/terms" rel="nofollow ugc">AltGenAI Terms of Service</a> and <a href="https://altgenai.com/privacy" rel="nofollow ugc">Privacy Policy</a>.</li>
</ul>

AltGenAI

AI-powered alt text for WordPress images. Works with the block editor, Classic Editor, the Media Library, and bulk tools.

Connor Bulmer

AI Auto Alt Text Generator is a lightweight, privacy-conscious plugin that uses OpenAI vision-capable models (defaulting to GPT-5.4 nano, with GPT-5.4 mini and legacy GPT-4o mini options) 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.
<h3>✨ Key features</h3>
<ul>
<li>Automatic alt text on upload – set-and-forget accessibility.</li>
<li>Optional automatic image titles – improve SEO with descriptive titles.</li>
<li>One-click manual generation – “Generate Alt Text & Title” button in the Media Library.</li>
<li>Bulk update tool – batch-process existing images, including those that only have filename-based alt text, with a configurable pause between batches.</li>
<li>Prompt fine-tuning – supply site-wide context and optionally include the image file name.</li>
<li>Model selection – default to GPT-5.4 nano (fastest & cheapest) or switch to GPT-5.4 mini for higher quality; legacy GPT-4o mini and GPT-5 mini/nano remain available.</li>
<li>Image size & detail control – choose the resolution and level of visual detail sent.</li>
<li>Developer-friendly – filters and actions to customise prompts, models and output, plus optional outgoing webhooks.</li>
<li>WordPress Abilities API – registers a <code>generate-alt-text</code> ability (WordPress 6.9+/7.0) so core AI, agents and automation tools can generate alt text.</li>
<li>No extra servers – data flows only between your site and OpenAI; nothing is stored off-site.</li>
<li>Multilingual output – choose English (UK), English (US) or other popular languages. (English US is the default.)</li>
</ul>
<h3>🧭 Where to find the bulk tool</h3>
<ul>
<li>Tools → Bulk Alt Text Update</li>
<li>Media → Bulk Alt Text Update (shortcut that redirects to the Tools page)</li>
<li>Settings → Alt Text Generator includes a button linking straight to the bulk page</li>
</ul>
<h3>🧠 How it works</h3>
<ol>
<li>When an image is uploaded (or manually chosen), the plugin creates a temporary public URL for that image.</li>
<li>It sends the image – plus optional context such as the parent post title, your custom site context and the file name – to your selected OpenAI vision model.</li>
<li>OpenAI returns a concise description.
<ul>
<li>Alt text is stored in WordPress’ native <code>_wp_attachment_image_alt</code> field.</li>
<li>(Optional) The returned title is stored as the attachment post title.</li>
</ul>
</li>
<li>Nothing is cached or stored on OpenAI’s side; only the final strings live in your database.</li>
</ol>
<h3>Settings overview</h3>
<ul>
<li>OpenAI API Key – Required to connect to OpenAI.</li>
<li>OpenAI Model – GPT-5.4 nano (default), GPT-5.4 mini, or legacy GPT-4o mini / GPT-5 mini / GPT-5 nano.</li>
<li>Image Size to Send – Thumbnail, Medium, Large, or Full.</li>
<li>Image Detail Quality – ‘Low’ or ‘High’ (Low uses fewer tokens).</li>
<li>Bulk batch size – Number of images per batch (lower values reduce rate-limit risk).</li>
<li>Site Context – Optional free-form prompt guidance (brand voice, niche, etc.).</li>
<li>Send Image File Name – Include file name in the prompt for extra context.</li>
<li>Automatically Generate Title – Add descriptive titles alongside alt text.</li>
<li>Use full context for image titles – When enabled, title generation includes site context and file name (uses more tokens).</li>
<li>Bulk optimiser delay (seconds) – Pause between batches during bulk runs.</li>
<li>OpenAI request timeout (seconds) – Max wait time for OpenAI responses (10–120s) to reduce timeout failures on slower hosts.</li>
<li>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.</li>
<li>Webhook URL & signing secret – Optionally POST generated alt text/titles to an external endpoint (with an optional HMAC-SHA256 signature) for automation and logging.</li>
</ul>
<h3>Developers</h3>
The plugin is extensible via standard WordPress hooks, an outgoing webhook, and the WordPress Abilities API.
Filters
<ul>
<li><code>aatg_alt_text_prompt</code> ( $prompt, $post_ID, $context ) – customise the alt-text prompt.</li>
<li><code>aatg_image_title_prompt</code> ( $prompt, $post_ID, $context ) – customise the title prompt.</li>
<li><code>aatg_openai_request_payload</code> ( $payload, $context, $messages ) – customise the full OpenAI request (model, messages, reasoning effort).</li>
<li><code>aatg_generated_alt_text</code> ( $alt_text, $post_ID ) – filter alt text before it is saved.</li>
<li><code>aatg_generated_title</code> ( $title, $post_ID ) – filter the title before it is saved.</li>
<li><code>aatg_is_low_quality_alt</code> ( $is_low, $alt, $post_ID ) – control which existing alt text the bulk tool regenerates.</li>
<li><code>aatg_webhook_payload</code> ( $payload, $post_ID, $result ) – customise the outgoing webhook body.</li>
<li><code>aatg_supported_image_extensions</code> ( $extensions ) – customise which image formats are sent to OpenAI (default: PNG, JPEG, GIF, WebP).</li>
</ul>
Actions
<ul>
<li><code>aatg_after_alt_text_generated</code> ( $post_ID, $alt_text )</li>
<li><code>aatg_after_title_generated</code> ( $post_ID, $title )</li>
<li><code>aatg_after_generation</code> ( $post_ID, $result )</li>
</ul>
Outgoing webhook
Set a Webhook URL under Settings → Integrations & Webhooks to receive a non-blocking JSON POST after each generation. If a signing secret is set, requests include an <code>X-AATG-Signature: sha256=…</code> header (HMAC-SHA256 of the body) so your endpoint can verify authenticity.
WordPress Abilities API
On WordPress 6.9+ the plugin registers the ability <code>ai-auto-alt-text/generate-alt-text</code> (input: <code>attachment_id</code>) so WordPress core AI, agents, MCP servers and automation tools can generate alt text programmatically. Execute it with <code>wp_get_ability( 'ai-auto-alt-text/generate-alt-text' )->execute( array( 'attachment_id' => 123 ) )</code>.
<h3>External services</h3>
This plugin connects to the OpenAI API to generate alt text and (optionally) image titles.
<ul>
<li>Endpoint: <code>https://api.openai.com/v1/chat/completions</code></li>
<li>When called:
<ul>
<li>On image upload (automatic)</li>
<li>Via “Generate Alt Text & Title” button in Media Library (manual)</li>
<li>Via Tools → Bulk Alt Text Update (bulk)</li>
</ul>
</li>
<li>Data sent: image URL, optional file name, optional site context, optional parent post title</li>
<li>Terms: <a href="https://openai.com/policies/terms-of-use" rel="nofollow ugc">https://openai.com/policies/terms-of-use</a></li>
<li>Privacy: <a href="https://openai.com/policies/privacy-policy" rel="nofollow ugc">https://openai.com/policies/privacy-policy</a></li>
</ul>
If you configure a Webhook URL, generated alt text/titles (and the image URL) are also sent to that endpoint you control.

AI Auto Alt Text Generator

Automatically generates alt text and image titles for your WordPress media uploads with selectable OpenAI models (defaulting to GPT-5.

AltGenAI vs AI Auto Alt Text Generator