Change 1000+ of WordPress Featured Images in 5 Minutes! › Forums › Questions and Answers › Pre-purchase Questions – Permanent or Filter? › Reply To: Pre-purchase Questions – Permanent or Filter?
Yes, that is possible. You can let the plugin in bulk in one single process: search for the first image, set it as featured, remove it from the post.
It is an “one-time function” and never called at page loads. So the removal is performed only once.
I highly recommend to make a backup before you run the plugin!