Offline
Without a network, pictures wait on the phone and go out in order when the connection is back.
If the network drops during a walk, the screen says Offline. The pictures wait on the phone and go out when the connection is back.
The pictures stay on the phone, in the order you took them. When the connection returns they are sent in that order. A tile clears when its picture is stored, not when you press the shutter. A retry sends the same picture. It is not stored twice.
Pause still keeps those waiting pictures. Finish walk still waits until they have been sent.