Set an already uploaded image as featured image of a post in WordPress

Question

I want to set featured images for different posts on WordPress website if the images are already uploaded on the server.

I plan on using the following code to do so:

// File has already been uploaded
$image_url = 'path/of/image';
if(file_exists($image_url)) {
    set_post_thumbnail($post_id, $image_id);
}

The problem is that I cannot figure out how to get the $image_id from just the image URL and nothing else. Is it possible in WordPress?

I would just like to clarify again that the image is already in the media library.

I have read this question: https://wordpress.stackexchange.com/questions/40301/how-do-i-set-a-featured-image-thumbnail-by-image-url-when-using-wp-insert-post but it does not tell me how to get the id of an image that is already in the media library.

I need something that is opposite of wp_get_attachment_url($id). This function returns the image path based on its id.

I want to get the image id based on its path or URL.

Thanks.

I understand you have uploaded a picture and you know the path , and now you want to create a thumbnail of that picture ? — user4038080
@HenryStack, No. :). I want to set that image as a featured image for a WordPress post. — Real Noob

dineshkashera dineshkashera · Accepted Answer · 2019-11-30T12:00:17

Please Use the below code :

$image_url = 'path/of/image';
if(file_exists($image_url)) {

    global $wpdb;
    $table_name = $wpdb->prefix . "posts";
    $attachment = $wpdb->get_col($wpdb->prepare("SELECT ID FROM $table_name WHERE guid='%s';", $image_url ));
    $image_id = $attachment[0]; 
    set_post_thumbnail($post_id, $image_id);

}

I hope it will help you.

Set an already uploaded image as featured image of a post in WordPress

2 Answers