据我所知image_size_names_choose 挂钩（参见https://codex.wordpress.org/Plugin_API/Filter_Reference/image_size_names_choose).

示例：

// add your custom size
function my_setup_image_sizes() {
  add_image_size( \'wide-image\', 900, 0);
}
add_action( \'after_setup_theme\', \'my_setup_image_sizes\' );

// add custom size to editor image size options
function my_editor_image_sizes( $sizes ) {
    $sizes = array_merge( $sizes, array(
      \'wide-image\' => __( \'Image 900px wide\' )
    ));
    return $sizes;
}
add_filter( \'image_size_names_choose\', \'my_editor_image_sizes\' );

NOTE 2 基本图像大小必须大于内部指定的尺寸add_image_size 作用