Digikam

Useful settings

Collections -> Ignored Directories -> #recycle (for synology)

Metatdata -> Behaviour -> Use Lazy Synchornization: makes you confirm the changes before writing them below. Useful when working on lots of pictures (eg face recognition)

Metatdata -> Behaviour -> Face tags + geolocation information on

Metadata -> Sidecars -> write and read on.

Miscellaneous -> Behaviour -> Scan for new items at startup, fast scan, detect faces in newly added images

Miscellaneous -> Behaviour -> Initially select the first item in the album

Faces

In the preview you can select show face tags on and off in the top left of the preview picture

To remove a face, right click on a picture, remove tag and then select the person to remove