Garmin asserts that the Messenger Plus is not the average inReach standalone satellite communicator. It is the first of its line to support photo- and voice note-sending in the complete absence of conventional cellular service. The new accessory is also capable of two-way texts, regular location updates and SOS features.https://www.notebookcheck.net/Garmin-inReach-Messenger-Plus-debuts-with-series-first-picture-and-voice-message-support.890526.0.html
Garmin 'inReach' devices use the 'iridium' network of LEO birds...
As such, one may (or NOT!) be overhead at any given time AND more importantly the bit rate these SAT's operate at is rather dismal (<=2400baud).
Therein leaving the time & odds of transferring an image of any size questionable at best.