Close file after writing raw image.
Close file after writing raw image.

* Fixes #365

kwagyeman/openmv,kwagyeman/openmv,kwagyeman/openmv,kwagyeman/openmv,openmv/openmv,openmv/openmv,iabdalkader/openmv,iabdalkader/openmv,openmv/openmv,openmv/openmv,iabdalkader/openmv,iabdalkader/openmv