void RSL_volume_to_pict(Volume *v, char *basename, int xdim, int ydim, float range);
void RSL_volume_to_ppm(Volume *v, char *basename, int xdim, int ydim, float range);
void RSL_write_gif(char *outfile, unsigned char *image,
void RSL_volume_to_pict(Volume *v, char *basename, int xdim, int ydim, float range);
void RSL_volume_to_ppm(Volume *v, char *basename, int xdim, int ydim, float range);
void RSL_write_gif(char *outfile, unsigned char *image,