How to include *.webp files in sync?

Help
1

What I’m trying to do

I try to sync graphic files with the extention “webp”.

Things I have tried

I turned on
Sync pictures (“Bilder synchronisieren”)
Sync all others (“Alle anderen Dateien synchronisieren”)

but no result. Error message could not be found (“… .webp konnte nicht gefunden werden”)

Any idea how to solve the problem?

Thanks in advance for your effort!

Greetings

2

Have you changed the settings on all devices?