Automatically save Images to Gallery

**Is your feature request related to a problem? Please describe.**
I did not find an option to save all received images directly to the gallery, so a user has to save every image manually to see it in the gallery.

**Describe the solution you'd like**
It would be nice if there is a global opt in setting, to save all received images automatically to the gallery.

**Describe alternatives you've considered**
Additionally it would be nice to have the option for each room to save all received images automatically to the gallery, so the user can activate this feature only for some rooms.