Go to Each file and press Edit >>Undo or Edit >>Revert option.
Or dowload any action which perform Undo opeartion on all your open files.
Did you choose a different source folder and destination folder. If so your originals should still be on your hard drive.
Did someone every answer this? Because we just had the same thing happen, the action didn't work the way we told it to and now we are going to have re-edit a bunch of pictures.
I am running into the same issue. Work around is not working. There really should be an alert that says 'Hey! Do you really mean to resize these to 8.5 by 10 pixels? You may want inches." Yay for updates that reset preferences! < Said no one ever.