It's worse than that - as you might suspect from needing a writable directory, it replaces the file. After first truncating it! So all the other hard-links to the processed files are broken, and I've got a bunch now zero-length files where the other links to the pictures used to be :-(
I'd really, really like it to write to the target files in-place, as it should by the Principle of Least Surprise. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org