Hey @amateurhr – Thanks for reaching out, as well as for using our plugin.
To make it work there are a couple of ways.
If you want to upload the image within your WordPress site in the first place, you can use the create_url_attachment webhook aciton within the “WordPress” integration. This one contains an argument called “add_post_thumbnail” in which you can set the post id you want to assing the image to.
If you only want to connect an existing image as a thumbnail to a specific post, you can use the update_post webhook action in combination with the manage_meta_data argument.
WordPress assings a featured image via the post meta using the _thumbnail_id meta key. If you set the id of your image to this meta key with the update_post_meta key, the image will be assinged correctly.
Feel free to reach out again in case you have any further questions.