Laut Entwickler unter 10.13 nicht mehr benötigt
http://externaleditorsforphotos.tumblr.com
>IMPORTANT: I removed the application from the Mac App Store because with the “High Sierra” release external editors are now natively supported in the Photos app (again).
>IMPORTANT: I removed the application from the Mac App Store because with the “High Sierra” release external editors are now natively supported in the Photos app (again).