Generate image alt from the post title -- for the first image in the post [WordPress]

generate_alt_from_title.php

// Generate image alt from the post title -- for the first image in the post
add_filter('the_content', 'add_alt_tags', 99999);
function add_alt_tags($content) {
	global $post;
	preg_match_all('/<img[^>]+>/i', $content, $images);
	if(!is_null($images)) 	{
		foreach($images[0] as $index => $value) {
			//If no alt
		//	if(!preg_match('/alt=/', $value)) {
				$new_img = str_replace('<img', '<img alt="'.get_the_title().'"', $images[0][$index]);
			//	var_dump($new_img);
				$content = str_replace($images[0][$index], $new_img, $content);
				//Just for the first image in post
				break;
		//	}
		}
	}

	return $content;
}