Media | Type: PHPUnset Intermediate Thumbnails

Sometimes you don’t need intermediate sizes. Snippet shows you how to lose them.

function add_image_insert_override( $sizes ){
    //unset( $sizes[ 'thumbnail' ]);
    unset( $sizes[ 'medium' ]);
    unset( $sizes[ 'medium_large' ] ); //768px wide (added in 2016)
    unset( $sizes[ 'large' ]);
    //unset( $sizes[ 'full' ] );
    return $sizes;
}
add_filter( 'intermediate_image_sizes_advanced', 'add_image_insert_override' );