This isn't a problem, I am just curious!
I connected an external 1TB USB Drive and a 32GB Flash Drive to my 1000s yesterday to test playback of my TV Series (MKVs). On both drives, for each episode/file played, the box seems to have created two files: an HMI File (.hmi) and an Image File (.png), in the same Folder as the episode.
The image is just a random screen shot (for a Thumbnail?).
Anyone know why it's creating these?