Registered thumbnails

Hi Catherine,

No, GeneratePress does not register any custom thumbnail sizes. The theme relies entirely on WordPress’s default image sizes.

I still get 1536×1157 and 768×578 images when I regenerate thumbnails and I don’t know why.

Those are WordPress core’s hidden image sizes that don’t appear in Settings > Media. You can try adding the snippet below to disable them:

// Disable WordPress's hidden image sizes
  function disable_wordpress_responsive_images() {
      // Disable medium_large size (768px)
      update_option( 'medium_large_size_w', 0 );
      update_option( 'medium_large_size_h', 0 );

      // Remove 1536x1536 and 2048x2048 sizes
      remove_image_size( '1536x1536' );
      remove_image_size( '2048x2048' );
  }
  add_action( 'init', 'disable_wordpress_responsive_images' );

  // Also prevent them from being generated
  add_filter( 'intermediate_image_sizes', function( $sizes ) {
      return array_diff( $sizes, array( 'medium_large', '1536x1536', '2048x2048' ) );
  });

Adding PHP: https://docs.generatepress.com/article/adding-php/

After adding the snippet, regenerate your thumbnails again — those sizes should no longer be created.