Adding this snippet to the functions.php of your wordpress theme will check if an option was updated by a user. If so, it will save it back to the default option you’ve set. Should work with almost any site option. (inspect element on input field and input’s “id” should be the “name” you need.)

[code lang=”php”]
$options = array(
    array( ‘name’ => ‘thumbnail_size_w’, ‘value’ => ‘150’ ),
    array( ‘name’ => ‘thumbnail_size_h’, ‘value’ => ‘150’ ),
    array( ‘name’ => ‘medium_size_w’, ‘value’ => ‘250’ ),
    array( ‘name’ => ‘medium_size_h’, ‘value’ => ‘250’ ),
    array( ‘name’ => ‘large_size_w’, ‘value’ => ‘728’ ),
    array( ‘name’ => ‘large_size_h’, ‘value’ => ‘728’ ),
    array( ‘name’ => ’embed_size_w’, ‘value’ => ‘728’ ),
    array( ‘name’ => ’embed_size_h’, ‘value’ => ‘600’ ),
);
foreach ( $options as $option ) {
    if ( get_option( $option[‘name’] ) != $option[‘value’] ) {
        update_option( $option[‘name’], $option[‘value’] );
    } else {
        $deprecated = ‘ ‘;
        $autoload = ‘no’;
        add_option( $option[‘name’], $option[‘value’],
$deprecated, $autoload );
    }
}
[/code]