\param number When positive, represents an index added to the filename. Otherwise, no number is added.
      \param digits Number of digits used for adding the number to the filename.
    **/
    const CImgList<T>& save(const char *const filename, const int number=-1, const unsigned int digits=6) const {
      if (!filename)
        throw CImgArgumentException(_cimglist_instance
                                    "save(): Specified filename is (null).",
                                    cimglist_instance);
      // Do not test for empty instances, since .cimg format is able to manage empty instances.
      const bool is_stdout = *filename=='-' && (!filename[1] || filename[1]=='.');
      const char *const ext = cimg::split_filename(filename);
      CImg<charT> nfilename(1024);
      const char *const fn = is_stdout?filename:number>=0?cimg::number_filename(filename,number,digits,nfilename):
        filename;

#ifdef cimglist_save_plugin
      cimglist_save_plugin(fn);
#endif
#ifdef cimglist_save_plugin1
      cimglist_save_plugin1(fn);
#endif
#ifdef cimglist_save_plugin2
      cimglist_save_plugin2(fn);
#endif
#ifdef cimglist_save_plugin3
      cimglist_save_plugin3(fn);
#endif
#ifdef cimglist_save_plugin4
      cimglist_save_plugin4(fn);
#endif
#ifdef cimglist_save_plugin5
      cimglist_save_plugin5(fn);
#endif
#ifdef cimglist_save_plugin6
      cimglist_save_plugin6(fn);
#endif
#ifdef cimglist_save_plugin7
      cimglist_save_plugin7(fn);
#endif
#ifdef cimglist_save_plugin8
      cimglist_save_plugin8(fn);
#endif
      if (!cimg::strcasecmp(ext,"cimgz")) return save_cimg(fn,true);
      else if (!cimg::strcasecmp(ext,"cimg") || !*ext) return save_cimg(fn,false);
      else if (!cimg::strcasecmp(ext,"yuv")) return save_yuv(fn,444,true);
      else if (!cimg::strcasecmp(ext,"avi") ||
               !cimg::strcasecmp(ext,"mov") ||
               !cimg::strcasecmp(ext,"asf") ||
               !cimg::strcasecmp(ext,"divx") ||
               !cimg::strcasecmp(ext,"flv") ||
               !cimg::strcasecmp(ext,"mpg") ||
               !cimg::strcasecmp(ext,"m1v") ||
               !cimg::strcasecmp(ext,"m2v") ||
               !cimg::strcasecmp(ext,"m4v") ||
               !cimg::strcasecmp(ext,"mjp") ||
               !cimg::strcasecmp(ext,"mp4") ||
               !cimg::strcasecmp(ext,"mkv") ||
               !cimg::strcasecmp(ext,"mpe") ||
               !cimg::strcasecmp(ext,"movie") ||
               !cimg::strcasecmp(ext,"ogm") ||
               !cimg::strcasecmp(ext,"ogg") ||
               !cimg::strcasecmp(ext,"ogv") ||
               !cimg::strcasecmp(ext,"qt") ||
               !cimg::strcasecmp(ext,"rm") ||
               !cimg::strcasecmp(ext,"vob") ||
               !cimg::strcasecmp(ext,"webm") ||
               !cimg::strcasecmp(ext,"wmv") ||
               !cimg::strcasecmp(ext,"xvid") ||
               !cimg::strcasecmp(ext,"mpeg")) return save_video(fn);
#ifdef cimg_use_tiff
      else if (!cimg::strcasecmp(ext,"tif") ||
          !cimg::strcasecmp(ext,"tiff")) return save_tiff(fn);
#endif
      else if (!cimg::strcasecmp(ext,"gz")) return save_gzip_external(fn);
      else {
        if (_width==1) _data[0].save(fn,-1);
        else cimglist_for(*this,l) { _data[l].save(fn,is_stdout?-1:l); if (is_stdout) std::fputc(EOF,cimg::_stdout()); }