filter-admin-post-thumbnail-size.md

Post Thumbnail Size Filter

Covers the following filters:

• admin_post_thumbnail_size

Overview

This filter fires when generating the image to be displayed in the Featured Image meta box. It's documented in the WordPress developer handbook.

Existing Usage

One existing used defined in WordPress/gutenberg#7505 is:

For a UX best practice I want to show the same size version of the image in the admin as on the frontend. And for listing pages, I sometimes use specific other or custom image sizes. That's what I want to be able to reflect in the admin as well.

Please open a new issue to suggest additional examples of existing usage.

Gutenberg Equivalent

PostFeaturedImage is a React component used to render the Post Featured Image selection tool. It includes a wp.hooks filter editor.PostFeaturedImage.imageSize (introduced in Gutenberg v3.4 with WordPress/gutenberg#8196) that enables developers to define a custom size for the image displayed.

Example:

var withImageSize = function( size, mediaId, postId ) {
	return 'large';
};

wp.hooks.addFilter( 'editor.PostFeaturedImage.imageSize', 'my-plugin/with-image-size', withImageSize );