Add image attachment to post via coding?

Question

I tried to add an image as Attachment image to a post. in wp_postmeta i added _wp_attached_file as meta_key and value = productimages/Routers/v/CISCO1941.jpg it not works and i could not see the image as attachment! but when i use add image button in wordpress's HTML editor, it add exactly this field to that table but with a different post ID!

is there any dependency for that field? screenshot from db: https://i.sstatic.net/mVlse.png

Answer 1

You do not add image attachment to post. In WordPress image attachment is also post. See post types in Codex.

• what is usually called post on surface is technically post of post post type.

• image attachment is a post of attachment post type.

So what you need to do is to create image attachment (using wp_insert_attachment() and couple more related functions) and set your post as parent for it.

Answer 2

Like what Rarst mentioned, you technically want to set the attachment's post_parent value to the ID of the post you are attaching it to.

e.g. you can do something like this:

wp_update_post( array(
        'ID' => $attachment_id,
        'post_parent' => $post_id
    )
);

However, please take note of the caution when using wp_update_post.

Another method using $wpdb

global $wpdb;
$wpdb->query(
    "
    UPDATE $wpdb->posts 
    SET post_parent = $post_id
    WHERE ID = $attachment_id
        AND post_type = 'attachment'
    "
);