Hi there – I am looking to set an image custom field as a featured image for a custom post type
I have changed the field name to mine (resource_image) but no luck
I have tried adapting some code found in this thread: https://support.advancedcustomfields.com/forums/topic/set-image-as-featured-image/
function acf_set_featured_image( $value, $post_id, $field ){
if(isset($value) && is_array($value)){
delete_post_thumbnail( $post_id);
//Add the value which is the image ID to the _thumbnail_id meta data for the current post
add_post_meta($post_id, '_thumbnail_id', $value[0][resource_image]);
}
return $value;
}
// acf/update_value/name={$field_name} - filter for a specific field based on it's name
add_filter('acf/update_value/name=resource_image', 'acf_set_featured_image', 10, 3);
Any idea what I am doing wrong
Did you try the code exactly as Jonathan posted it and only changing the field name?
<?php
function acf_set_featured_image( $value, $post_id, $field ){
if($value != ''){
//Add the value which is the image ID to the _thumbnail_id meta data for the current post
add_post_meta($post_id, '_thumbnail_id', $value);
}
return $value;
}
// acf/update_value/name={$field_name} - filter for a specific field based on it's name
add_filter('acf/update_value/name=cursusfoto', 'acf_set_featured_image', 10, 3);
?>
I know this is an old topic, but after doing this for some time I’ve just recently realized that using a filter isn’t needed. All you really need to do is create an image field with the field name of “_thumbnail_id”, and ACF will just update the featured image for you. There’s no error checking, but simply making your image field required deals what that problem.
Just thought I add this for anyone that finds this topic.
John…..
I’ve been using custom code to do this for years and now your solution seems to obvious! Thank you for posting this.
Although, that said, it doesn’t seem like a lot of work for Elliot to just have a toggle on the image field that sets the image as “featured” (and takes away the ability to set the slug). 🙂
Yes, it was too obvious. I mentally smacked myself in the head when I saw it because like everyone else I’ve been using an acf/save_post action on pretty much every site I’ve built since starting to use ACF, quite a few years ago now. Simply because I wanted to make the featured image required and be able to enforce specific image sizes for different sites/post types.
The only real problem with using this method is that get_fields() will not return this field. ACF ignores all fields that start with an underscore. These fields are also hidden by WP. But since I’ve never used get_fields() it works out fine for me.
Yeah, though I suppose the implication would be that you want to use the_post_thumbnail() (and other related functions) anyway, if you’re trying to auto-set the featured image, so not a huge downfall.
