What will store in file stream column ?

Hi All,
    This is basic level question i asked, what will store in varbinary(MAX) column in File Stream table ?
1. Is it store file as binary ?
2. Is it store path of disk NT files ?

Because when we store files in that column, that column size will increase when we get size of varbinary column, is it return size of file in disk ? or if only pointer means why it increase  ?

If i check in file stream folder i can see same size of file which i store in sql sever, if it store file in stream folder, then why return file size in varbinary column,i use this query to get size on column "SELECT DATALENGTH(Document) AS FIELDSIZE  FROM FileTable"

In same table i store file name also, when i get size of filename column it return small size only.

shreenshot 

Pls reply asap,

Regards,
Aravind