A timed (maybe 2s) notification appears in a corner telling the user that there are no more files. While the notification is visible the user has two options:
Do nothing OR
Press → again. Either of these things should happen
Open folder selector OR
Open first file OR
Do nothing
In settings:
Behaviour when hitting folder end: (as radio buttons)
Use-case:
At last image of a folder
In settings: Behaviour when hitting folder end: (as radio buttons)