Last updated on March 19th, 2022 at 10:56 am

To remove all the image sizes keeping only the default WordPress image sizes (source) :

function remove_extra_image_sizes() {
    foreach ( get_intermediate_image_sizes() as $size ) {
        if ( !in_array( $size, array( 'thumbnail', 'medium', 'medium_large', 'large' ) ) ) {
            remove_image_size( $size );
        }
    }
}
 
add_action('init', 'remove_extra_image_sizes');

To enable shortcodes in widgets:

To add “last updated” timestamp to your content: