Does This App Upload My Photos Anywhere?
No. Everything happens on your own computer. There is no account and no upload.
No. The photos are read from your disk and written back to your disk. Nothing is sent anywhere, there is no account to create, and there is no server holding a copy.
The one exception is optional, and it is off unless you turn it on: looking up a place name sends the coordinates, and nothing else, to a mapping service. Leave it off and the app never touches the network.
That is also why it keeps working with the wifi off, on a plane or on a machine that never goes online. It runs on your own computer and is free for your first 500 photos.