WordPress中自动为文章内容的图片添加文章标题作为alt属性

//添加文章标题作为alt属性
function add_image_alt_title_tags($content) {
global $post;
$post_title = $post->post_title;
$pattern = '/<img(.*?)\/>/i';
preg_match_all($pattern, $content, $matches);
$image_count = count($matches[0]);
foreach ($matches[0] as $index => $img_tag) {
if (strpos($img_tag, ' alt=') === false || preg_match('/ alt=["\']\s*["\']/', $img_tag)) {
if ($image_count === 1) {
// 如果只有一张图片，不添加序号
$replacement = preg_replace('/<img/', '<img alt="' . $post_title . '" title="' . $post_title . '"', $img_tag);
} else {
// 如果有多张图片，添加序号
$replacement = preg_replace('/<img/', '<img alt="' . $post_title . '-' . ($index + 1) . '" title="' . $post_title . '-' . ($index + 1) . '"', $img_tag);
}
$content = str_replace($img_tag, $replacement, $content);
}
}
return $content;
}
add_filter('the_content', 'add_image_alt_title_tags');