ftp_size
    (PHP 3>= 3.0.13, PHP 4 )
ftp_size -- Returns the size of the given file
Description
int 
ftp_size ( resource ftp_stream, string remote_file)
     ftp_size() returns the size of a file in bytes.  If an
     error occurs, of if the file does not exist, -1 is returned.  Not
     all servers support this feature.
    
     Returns the file size on success, or -1 on error.