Here is a way to hide your files:
Go to Fileman.
Go to the desired file
Select options and got to operations and select Set Attr (Attributes).
Select hidden on.
( Please See that you scroll down as Set Attr is not normally visible )
If you want nobody to search for the file rename it.
(For example change .jpg file into .reg)
Go to Open With...
In Application change the blank one.
If you follow the above way your files will not be visible on your PC unless viewing hidden files is enabled.