You can use Simple SEO Improvements WordPress plugin, which is integrated with OG.

Or use the filter “og_image_init”:

add_filter('og_image_init', 'my_og_image_init');
function my_og_image_init($images)
{
    if ( is_front_page() || is_home() ) {
        $images[] = 'https://wordpress/wp-content/uploads/2014/11/DSCN0570.jpg';
    }
    return $images;
}