Auto Post Thumbnail Plus

Minimal WordPress plugin that automatically sets featured images for posts that don't have one.

---

📋 Description

Auto Post Thumbnail Plus is a lightweight plugin that automatically assigns featured images to posts that don't have one. Choose between extracting the first image from content or using a default fallback image.

Why do you need this plugin?

Featured images are essential for modern WordPress sites. This plugin:

✅ Improves SEO - Every post has a featured image for social sharing
✅ Saves time - No manual featured image assignment needed
✅ Consistent design - All posts have thumbnails in archives and grids
✅ Smart detection - Automatically finds and downloads external images

---

✨ Features

🎯 Core Features

• Automatic featured image assignment - Works on post save/publish
• Two intelligent modes:
  • First Image Mode - Extracts first image from post content (with external image download)
  • Default Image Mode - Uses a pre-selected fallback image
• Theme-agnostic - Works with any WordPress theme
• Simple ON/OFF toggle - Easy control in Settings → Media
• External image support - Downloads and imports external images to Media Library

🎁 Advanced Features

• Skip pages - Option to only apply to blog posts (not pages)
• Bulk apply - Retroactively set featured images for existing posts
• Debug logging - Detailed logs when WP_DEBUG is enabled
• Smart validation - Prevents duplicate processing and validates images
• Media Library integration - Seamless image picker interface

---

🚀 Installation

Automatic installation (WordPress.org)

1. Go to Plugins → Add New
2. Search for "Auto Post Thumbnail Plus"
3. Click "Install Now" and then "Activate"
4. Configure in Settings → Media

Manual installation

1. Download plugin files
2. Upload folder to /wp-content/plugins/
3. Activate plugin through Plugins menu
4. Go to Settings → Media to configure

---

📖 Usage

Admin Panel

1. Go to Settings → Media
2. Find "Auto Featured Image Settings" section
3. Configure options:
   • ☑ Enable auto-featured-image - Main toggle
   • Mode: Choose between first image or default image
   • Default image: Select fallback image (for default mode)
4. Expand Advanced Options for:
   • ☑ Skip pages - Only apply to posts
   • ☑ Enable debug logging - Troubleshooting logs
   • Bulk Apply - Process existing posts
5. Save changes

First Image Mode

When enabled, plugin will:

1. Check post content for <img> tags
2. Look for wp-image-{id} class (WordPress Media Library images)
3. Extract image URL from src attribute
4. If image is external - download and import to Media Library
5. Set as featured image

Example:

<!-- This image will be automatically set as featured image -->
<img src="https://example.com/image.jpg" alt="Post image">

Default Image Mode

When enabled, plugin will:

1. Use pre-selected image from Media Library
2. Apply to all posts without featured images
3. Perfect for blogs with consistent branding

Bulk Apply

To apply featured images to existing posts:

1. Go to Settings → Media
2. Expand "Advanced Options"
3. Click "Apply to Existing Posts Without Featured Image"
4. Wait for processing (shows success/skip count)

Bulk apply will:

• Only process published posts without featured images
• Respect your chosen mode (first image or default)
• Skip posts without images (in first image mode)
• Process in background with AJAX

---

🔧 Technical Details

WordPress Hooks

Plugin uses the following hooks:

• save_post - Triggers on post save
• publish_post - Triggers when post is published
• wp_insert_post - Triggers on new post creation
• admin_init - Registers settings
• admin_menu - Adds settings link
• wp_ajax_aptp_bulk_apply - AJAX bulk processing

What happens on post save?

1. Plugin checks if featured image already exists
2. Validates post type (post/page)
3. Checks if plugin is enabled
4. Processes based on selected mode:
   • First Image: Extracts from content, downloads if external
   • Default Image: Applies pre-selected image
5. Sets featured image with set_post_thumbnail()

External Image Download

Plugin automatically downloads external images:

1. Validates URL format
2. Downloads to temporary location
3. Uploads to WordPress Media Library
4. Attaches to post
5. Cleans up temporary files

Supported formats: JPG, PNG, GIF, WebP, SVG (any WordPress-supported image)

---

📦 File Structure

auto-post-thumbnail-plus/
├── auto-post-thumbnail-plus.php  # Main plugin file (~724 lines)
├── assets/
│   ├── js/
│   │   └── admin.js              # Media picker + AJAX
│   └── css/
│       └── admin.css             # Minimalist admin styling
├── languages/
│   ├── auto-post-thumbnail-plus.pot  # Translation template
│   └── README.md                 # Translation guide
├── readme.txt                    # WordPress.org readme
├── README.md                     # This documentation
├── FEATURES.md                   # Feature summary
├── FUNCTIONALITY.md              # Technical docs (Serbian)
└── UI-DESIGN.md                  # Admin UI design

---

🎨 Performance & SEO

• ⚡ Fast - Minimal overhead, efficient hooks
• 🪶 Lightweight - ~724 lines of clean code
• 🔍 SEO friendly - Every post has Open Graph images
• 🎯 Smart processing - Only processes when needed
• 🌐 Theme-agnostic - Works with any theme
• 📱 Social sharing ready - Featured images for Facebook, Twitter, LinkedIn

---

📋 Requirements

• WordPress: 5.0 or newer (tested up to 6.8)
• PHP: 7.2 or newer
• MySQL: 5.6 or newer (WordPress standard)

---

❓ FAQ

Does it work with external images?

Yes! Plugin automatically downloads external images from post content and imports them to your Media Library.

What happens if post already has a featured image?

Plugin skips posts that already have featured images. It never overwrites existing ones.

Does it work with Gutenberg?

Yes! Plugin is editor-agnostic and works with Classic Editor, Gutenberg, and page builders.

Can I bulk apply to existing posts?

Yes! Use the "Apply to Existing Posts Without Featured Image" button in Advanced Options.

Does it affect pages?

By default yes, but you can enable "Skip pages" option to only process blog posts.

Does it slow down the site?

No. Plugin only runs on post save/publish (not on page load). Minimal performance impact.

What if post has no images?

In first image mode, post is skipped. In default image mode, default image is applied.

Can I see what's happening?

Yes! Enable "Debug logging" in Advanced Options. Logs are written to wp-content/debug.log when WP_DEBUG is enabled.

Does it work with any theme?

Yes! Plugin uses standard WordPress functions (set_post_thumbnail) which work with all themes.

What about custom post types?

Currently only supports post and page post types (configurable with "Skip pages" option).

---

🌍 Translations

Plugin is translation-ready with .pot file included in languages/ folder.

Currently available:

• English (default)

Want to translate?

• Use Poedit to create .po file
• Submit translation via GitHub
• Or via WordPress.org GlotPress

---

📄 License

GPL v2 or later - https://www.gnu.org/licenses/gpl-2.0.html

---

👨‍💻 Author

Bitwise Software
Website: bitwisesoftware.rs
GitHub: @Bitwise-SoftwarePR

---

🐛 Support

For help:

• GitHub Issues: github.com/Bitwise-SoftwarePR/AutoPostThumbnailPlus/issues
• WordPress.org Support: wordpress.org/support/plugin/auto-post-thumbnail-plus/

---

🤝 Contributing

Pull requests are welcome! For major changes, please open an issue first.

Development

# Clone repository
git clone https://github.com/Bitwise-SoftwarePR/AutoPostThumbnailPlus.git

# Install in WordPress
cp -r AutoPostThumbnailPlus /path/to/wordpress/wp-content/plugins/

---

📝 Changelog

1.0.0 - 2025-11-18

• 🎉 Initial release
• ✅ Automatic featured image assignment
• ✅ Two modes: first image or default image
• ✅ External image download and import
• ✅ Bulk apply to existing posts
• ✅ Skip pages option
• ✅ Debug logging support
• ✅ Minimalist all-in-one admin UI
• ✅ WordPress 6.8 compatible
• ✅ Translation-ready with .pot file

---

Made with ❤️ for the WordPress community by Bitwise Software