Image alt tag is showing post title instead of Alt Text

Question

The image alt tag shows the post title in the source instead of the Alt Text.

function my_custom_image_sizes() {
    add_image_size('homepage-thumb', 329, 185, true);
}
add_action('after_setup_theme', 'my_custom_image_sizes');

function my_custom_thumbnails($html, $post_id, $post_image_id, $size, $attr) {
    if(is_home() && $size == 'large') {
        $size = 'homepage-thumb';
    } elseif(is_single() && $size == 'large') {
        $size = 'postpage-thumb';
    }

    $image = wp_get_attachment_image_src($post_image_id, $size);
    if ($image) {
        $html = '<img src="' . $image[0] . '" width="' . $image[1] . '" height="' . $image[2] . '" alt="' . get_the_title($post_id) . '">';
    }

    return $html;
}
add_filter('post_thumbnail_html', 'my_custom_thumbnails', 10, 5);

I just want the alt text that I put in the image section.

Answer 1

In the place where you use get_the_title($post_id) you need to get the alt attribute that is stored in the post metadata like this:

esc_attr (get_post_meta ($post_id, '_wp_attachment_image_alt', true))

Answer 2

You can use _wp_attachment_image_alt like @cjbj shows but I am adding an addition to it for the fall back.

   $alt_text = get_post_meta($post_image_id, '_wp_attachment_image_alt', true);
          // If ALT text is not set, fallback to the post title
         if (empty($alt_text)) {
             $alt_text = get_the_title($post_id);
           }

Please always use Fall Back for the such conditions as it will cause issue if there is no ALT tag found.