Periodically, icons will appear in my picture file on random dates--the icons look like little pages, and there are often many of them (see screen shot below). I cannot open them because their format cannot be found. Some can be deleted to the "Trash" bin, others cannot be deleted at all. What are these files and how do I a.) get rid of them; and, b.) prevent them from appearing in my picture file again? Have I been hacked?