i’ve a similar problem. I’m using Posteo for syncing contacts and calendar.
When i change/add a contact photo on my old Smartphone (Cyanogenmod11), on my new Smartphone (Android 5.1) or on my Tablet (Android 5.0) it doesn’t appear at Thunderbird or the other devices. But at Posteo i can see the changed photo. So the pictures seems to “leave” the Android Device.
When i change/add a picture in Posteo it appears at the Android Devices but not at Thunderbird (the old pictures disappears simply).
The only way to have a correct synchronization is to change the pictures in Thunderbird (Version 38.4.0 with SOGo Connector 31.0.1. I also use MoreFunctionsForAddressbook 0.7.3). Then i see the changed Pictures on the android devices and at the Posteo Website.
So i dont know exactly where the fault could be.
I contacted the Posteo Support weeks ago but until now i didn’t get a answer.
Maybe anybody has a idea?
At gitlab i couldnt post a snippet (Error: 404 The page you’re looking for could not be found) so i post my Debug-Info here. When i should do it otherwise, please let me know.
DAVdroid version: 0.9.1.2 (86) Fri Jan 01 14:07:08 MEZ 2016
Installed from: com.android.vending
JB Workaround installed: no
System-wide synchronization: automatically
Address book sync. interval: 1440 min
Calendar sync. interval: 1440 min
OpenTasks sync. interval: —
Android version: 5.1 (r4275.1_FP2_gms36_1.1.7)
Device: Fairphone FP2 (FP2)