Its main goal is to easly convert .heic images created by iPhones to other file types, like jpg or png.
It is utilizing the HEIF Image Extensions by Microsoft. You need to have it installed, otherwise it will not work.
You can install via the Setup.msi (built by the WiX project).
It will install the program to the program files folder and register some sub menu commands (Convert to -> jpg, png, etc...) for windows explorer in the registry.
The Convert to sub menu will only appear for .heic files.