+#if HAVE_PNG
+ void writeImagePNG (const char *outfile, int bitdepth, int nxcell, int nycell, double densmin, double densmax);
+#endif
+#if HAVE_GD
+ void writeImageGIF (const char *outfile, int nxcell, int nycell, double densmin, double densmax);
+#endif
+ void writeImagePGM (const char *outfile, int nxcell, int nycell, double densmin, double densmax);
+ void writeImagePGMASCII (const char *outfile, int nxcell, int nycell, double densmin, double densmax);