I only have Gen 1 Ford Sync - text based only (no screen), but the S7 connects and works fine. Calls over the sync system work fine, incoming texts work as well as connected Sync linked apps.
To answer your question we would need to know which generation of Sync that you have. I have gen 1 with navigation screen. I have personal pictures on my navigation screen but they aren't uploaded via the S7. I have to put them on a USB stick to upload. My S7 is compatible in every way except using the phone's ringer as the ringtone that the car produces. However I have not updated to the latest version of Ford Sync. Doing so may correct that issue.
I also have Sync text based only (no screen) Gen 1 v1.1. My S7 works fine with Ford Sync.
If you don't know what version of Sync you have you can log onto the website show below. Once logged on it will show you the Sync history of your vehicle.
I have a 2016 Ford Escape with the Sync 3 system. My S7 was no problem to set up. I receive and make phone calls with no problem and it reads my messages to me but I haven't tried putting any pictures on the sync system.