For that I have used the solution explained in:
C# Download all files and subdirectories through FTP
But I can not find the permission as explained there: ie.,
string permissions = tokens[0];
Also I got an error when I tried to download files to downloads .
error:Access to the path 'C:\Users\admin\Downloads\1_IMG_3139.JPG' is denied.
where 1_IMG_3139.JPG is the first image to be downloaded.