How to clear recently deleted in photos

I am moving away from syncing photos using cloud as this uses up too much space on all my devices, will now sync only selected folders using itunes.

SO to clear my photos appI tried removing all the photos, now after a lot of struggles there is still 15000 + images in the recently deleted tab, no previews available, restoring it also ends up in a blank image,

Tried empty in the setting, deleting only batches but still not getting rid of these blank images.

Please help.