Using iOS, I cannot find what I am doing wrong to delete local t'nails. I checked the "delete thumbnails on exit" and tried the "delete now". Neither worked even upon exit. I've manually deleted all camera files, but the t'nails remain.
The only way I have been able to delete is to single-select each t'nail, then hit delete button. But that does not work well with a high quantity of thumbnails that timelapses create. As a minimum, am I missing a way to group-select (i.e. like click, shift-click on desktop)?