Function stripped_path 

pub fn stripped_path(input: &Path, output_dir: Option<&Path>) -> PathBuf

Where a stripped copy goes: photo.jpg becomes photo.stripped.jpg, beside the input or in output_dir. Shared so every front-end names its output the same way.

The suffix goes before the extension so the file still opens in the right application, and the name is deliberately not a temporary-looking one — this is the file the user will publish.