void readtiff       (          char * file_name, tree &level);
void readtiff_Colour(          char * file_name, 
                               tree & R,
                               tree & G,
                               tree & B                     );
void writetiff      (          char * file_name, 
                      unsigned char * Image,
                               int    width, 
                               int    height                );
void writetiff_Colour(         char * file_name, 
                      unsigned char * Image,
                               int    width, 
                               int    height                );