[How to sync merge between exist folders]

I  try to  gallery sync between  two android phone 

How to sync merge between exist folders 

 

[Can't download file]

my solution is...

at only trouble equipment

"not use archive"  <- may be...... this is not chacing for rename or change...only copy from another peer   

                                     this option has risk no backup file

"use changing file overwrite" <--this is only viewing at 'read only mode'