"However, when it comes to sending private photos, there’s an even better way than messaging apps...#ProtonDrive."

Please explain, why ProtonDrive is more secure sharing photos than #Threema Libre. (Apart from the expiration date.
A password only helps, if the end-users' smartphone enables it. Once downloaded to the phone, it's as secure or less (you will always download a pic from a drive, whereas you don't need to in the #Threema timeline.)