I want to require a featured image or video id (custom field), and I am able to check the fields when the user tries to update the page (using the
pre_post_update hook) but the problem is that the user can click 'remove featured image' and the presence or absence of the image is saved to the database without clicking 'update'. Therefore, it does not go through the check for requiring the specified fields. What I want to know is if there is a way to capture when the user clicks 'remove featured image' so I can validate at that time as well. Thanks for the help!