No—file transfer itself normally does not reduce image quality. Moving a JPEG over Wi‑Fi or via AirDrop should copy the file unchanged rather than recompressing it.

With image files, random corruption in transit usually would not cause a subtle quality drop; it would more likely create obvious file errors or make the file unreadable. So if the JPEG arrives and looks normal, the transfer process likely preserved it.

The main caveat is whether any app in the workflow exports, resaves, or converts the image instead of sending the original file. If Panasonic Image App, Photos, or the upload app is passing along the original JPEG, quality should remain the same and metadata can remain intact.

Based on your described workflow, the transfers themselves are not expected to degrade the image. The only possible quality change would be if a service on the receiving end creates its own processed copy after upload.