Can't delete large thumbnail file

I have a very large thumbnail file on my phone (Note 2) which I can't delete. Does anyone know a way to get rid of it?

The file is: /storage/emulated/0/DCIM/.thumbnails/1383441028546.jpg

I've tried deleting it via 'My Files', 'Solid Explorer' and 'ES File Explorer' which all fail to delete the file.

Thanks.