Show stuff everywhere except single post?

The is_single is WordPress function so you should add parentheses after it as displayed in the following correct code.

<?php if ( ! is_single() ){ ?>
    <meta property="og:image" content="<?php echo get_template_directory_uri(); ?>/images/image.png"/>
<?php } ?>

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)