I know the coordinates of a photo, can I enter them manually?
On the locr website you can enter the coordinates without any problems. You can enter them in the following format:

Example: Brandenburger Tor, Berlin, Germany
Latitude: 52.516286°
Longitude: 13.377763°

If the coordinates are available in a different format, e.g. Degrees, Minutes, Seconds (Brandenburger Tor: Latitude=52°30´58.63"N, Longitude=13°22´39.95"E), you will have to convert them with a suitable tool prior.

Using locr GPS Photo the direct entry of the coordinates is not possible.