Featured Image Warning

Warns editors when a post is missing a featured image, in both the Classic Editor and Block Editor.

Description

Featured Image Warning displays a warning notice in the WordPress post editor whenever a featured image (thumbnail) has not been set.

This helps content editors remember to add a featured image before publishing, reducing the chance of posts going live without one.

Features

• Works with the Block Editor (Gutenberg): shows a warning in the pre-publish panel and in the post status sidebar.
• Works with the Classic Editor: shows an admin notice at the top of the edit screen.
• Automatically skips post types that do not support featured images.
• Lightweight — no settings page, no database queries beyond standard WordPress functions.

Supported languages

• English
• Japanese (日本語)

Installation

1. Upload the featured-image-warning folder to the /wp-content/plugins/ directory, or install the plugin through the WordPress Plugins screen directly.
2. Activate the plugin through the Plugins screen in WordPress.
3. That's it! Open any post or page that supports featured images and edit it — you'll see a warning if no featured image is set.

Frequently Asked Questions

Does this work with custom post types?

Yes. The plugin automatically detects whether a post type supports featured images (thumbnail) and only shows the warning for those post types.

Can I disable the warning for specific post types?

Not through a settings UI currently. You can use the fiw_supported_post_types filter (coming in a future release) or simply remove the support via remove_post_type_support().

Will this prevent publishing without a featured image?

No. The warning is informational only and does not block publishing.

Screenshots

1. Warning displayed in the Block Editor pre-publish panel.
2. Warning displayed in the Block Editor sidebar (post status area).
3. Warning displayed in the Classic Editor.

Changelog

1.0.0

• Initial release.

Upgrade Notice

1.0.0

Initial release.