A more appropriate hook may be delete_attachment($post_id)
. You may also need to hook edit_attachment
. Note that the post_id
is that of the attachment type post, not the page/blog post to which the media is attached (if any).
In case you want to know when media is added, hook add_attachment($post_id)
. Note that add_attachment
is called before intermediate size files are generated but after the media has been placed in the upload directory.