What happens when I delete a duplicate or click “Trash All” button in Duplicates dialog?
When you click the “Move all to Trash” button on the top panel – Phototheca moves all duplicates into Trash, keeping one original thumbnail per every duplicate in an Event where it appears first.
When you click the “Delete from disk” button then Phototheca delete files from disk, from the folder which relates to the button. Every folder with duplicates has its own “Delete from disk” button on the right, and the button works for the folder which is on left. You’ll be asked for confirmation before files are deleted.
Read more: Duplicates