ASB Post Thumbnail

ASB Post Thumbnail automatically generates a featured image for each post by combining the post title, categories, author name or any custom text with a design template. Images are generated when a post is saved, so every article gets a polished OGP image for social sharing — no design work required.

Key Features

• High-quality rendering engine — Uses ImageMagick (Imagick) for beautifully anti-aliased text when available, and falls back to the GD library automatically.
• Full Gutenberg integration — Live preview and one-click generation from a sidebar panel in the block editor.
• Three-layer layout — Place the post title, excerpt, category, author name, date or custom text freely on the top, middle and bottom layers.
• Bundled Japanese font — Noto Sans JP (Regular & Bold, SIL Open Font License 1.1) is included, so Japanese and Latin titles render beautifully out of the box.
• Japanese line-breaking rules (kinsoku) — Automatic word wrapping that keeps punctuation off the start of a line.
• Lightweight display copies (WebP / AVIF) — optional. Your pages serve a much smaller copy while the featured image itself stays a JPEG, so social cards, feeds and other plugins are untouched. Browsers that cannot read the copy fall back to the JPEG on their own.
• OGP-optimized size — 1200 x 630 by default, ideal for X (Twitter) and Facebook sharing.
• Live preview on the settings screen — See exactly what generated images will look like while you tweak the design.

Security and Performance

• REST API input is sanitized in multiple layers (SSRF and path traversal protection).
• Duplicate save_post calls from Gutenberg are suppressed with a static flag.
• Preview images are cleaned up by a daily cron job; previously auto-generated featured images are removed when a new one is generated (manually chosen images are never touched).
• The Imagick instance is reused during generation, keeping long titles fast to render.

Design Control

Everything below is included — there is no paid edition.

• Custom font upload (.ttf / .otf)
• Downloadable extra Japanese fonts (M PLUS Rounded 1c, Kaisei Tokumin, Sawarabi Mincho, Shippori Mincho, RocknRoll One, Noto Serif JP)
• Image layers — place a logo or any image on a layer
• Multiple background images with random or sequential rotation
• Overlay (semi-transparent color layer)
• Text stroke (outline), Y-axis offset and line-height fine-tuning
• Stack layout mode
• Custom post type support
• Synchronous generation mode (required for Jetpack social image integrations)
• Per-category / per-tag / per-post override rules (disable generation or apply a different design)
• Per-post setting overrides
• Permission settings tab

External services

The plugin connects to one third-party service, and only when an administrator asks it to.

Google Fonts (fonts.gstatic.com)

The settings screen offers a few optional Japanese fonts (listed under “Credits” below). When an administrator clicks “Download” next to one of them, your server downloads that font file from a fixed address on fonts.gstatic.com and saves it in the uploads folder, so the font can be used for generated images. Nothing is requested before the button is clicked, and nothing is requested again afterwards.

What is sent: an ordinary download request for that one file. Like any request WordPress makes, it carries your server’s IP address and your site’s address (WordPress’s standard User-Agent header). No post content, no user data and no visitor data are sent. Generated images are made on your own server and are never uploaded anywhere.

Terms of service: https://developers.google.com/fonts/terms
Privacy policy: https://policies.google.com/privacy

Source Code

This plugin ships with a compiled JavaScript bundle for the block-editor sidebar
UI: build/index.js, build/index.css and build/index-rtl.css. These are
generated from React/JSX source using the standard WordPress build toolchain
(@wordpress/scripts, i.e. webpack under the hood).

The human-readable source is included in this plugin, under editor-src/:

• editor-src/src/index.js — the React/JSX source of the sidebar panel
• editor-src/src/index.scss — its styles
• editor-src/package.json — build scripts and the single dev dependency
• editor-src/babel.config.js — the Babel settings used by the build
• editor-src/package-lock.json — the exact dependency tree
• editor-src/README.md — build instructions and a note on the shipped bundle

To rebuild, run npm install then npm run build inside editor-src/
(development watch build: npm start), and copy the resulting build/ files
over the plugin’s own build/ directory.

No third-party analytics, tracking or obfuscation is applied to the bundle.

Credits

• Bundled font: Noto Sans JP (SIL Open Font License 1.1)
• Select2 4.1.0 (MIT License), bundled unmodified in vendor/select2/ together with its unminified files (select2.js, select2.css): https://select2.org/ — source: https://github.com/select2/select2/tree/4.1.0
• Downloadable fonts: M PLUS Rounded 1c, Kaisei Tokumin, Sawarabi Mincho, Shippori Mincho, RocknRoll One, Noto Serif JP (SIL Open Font License 1.1), fetched from the Google Fonts CDN on request.