Hi,
This functionality is not implemented. The exporting option is just exporting the raw data. The easiest way to remove all depth images for the database is to edit manually the
database:
$ sqlite3 my_map.db "UPDATE Data SET depth = NULL;"
I am not sure if the database file will shrink. If not, check this post to rebuild the database after updating the "depth" field to null:
https://stackoverflow.com/a/7682690cheers,
Mathieu