There is a software error that needs correcting.
Go to Other-Gallery-Albums
Then at top right of screen there is a camera icon.
If you click on that icon the entire screen inverts and everything locks up.
The solution is to re-boot by turning off power switch, plug in charger for a few seconds,
remove charger, and turn on power switch again.
There does no seem to be any reason for the camera icon to be there.
This is not normally a problem for usual operations and is a minor issue.