Disable WordPress Image Sizes

/* Remove all image sizes keeping only the default WordPress image sizes */
add_action('init', 'remove_extra_image_sizes');
function remove_extra_image_sizes() {
    foreach ( get_intermediate_image_sizes() as $size ) {
        if ( !in_array( $size, array( 'thumbnail', 'large' ) ) ) {
            remove_image_size( $size );
        }
    }
}