diff --git a/splash/SplashBitmap.cc b/splash/SplashBitmap.cc
index 7c14b3161..22eaac90c 100644
--- a/splash/SplashBitmap.cc
+++ b/splash/SplashBitmap.cc
@@ -354,6 +354,8 @@ SplashError SplashBitmap::writeImgFile(SplashImageFileFormat format, FILE *f, in
   ImgWriter *writer;
 	SplashError e;
   
+  imageWriterFormat = splashModeRGB8;
+  
   switch (format) {
     #ifdef ENABLE_LIBPNG
     case splashFormatPng:
@@ -377,9 +379,11 @@ SplashError SplashBitmap::writeImgFile(SplashImageFileFormat format, FILE *f, in
       switch (mode) {
       case splashModeMono1:
         writer = new TiffWriter(TiffWriter::MONOCHROME);
+        imageWriterFormat = splashModeMono1;
         break;
       case splashModeMono8:
         writer = new TiffWriter(TiffWriter::GRAY);
+        imageWriterFormat = splashModeMono8;
         break;
       case splashModeRGB8:
       case splashModeBGR8:
@@ -744,41 +748,83 @@ SplashError SplashBitmap::writeImgFile(ImgWriter *writer, FILE *f, int hDPI, int
     
     case splashModeMono8:
     {
-      unsigned char *row = new unsigned char[3 * width];
-      for (int y = 0; y < height; y++) {
-        // Convert into a PNG row
-        for (int x = 0; x < width; x++) {
-          row[3*x] = data[y * rowSize + x];
-          row[3*x+1] = data[y * rowSize + x];
-          row[3*x+2] = data[y * rowSize + x];
-        }
+      if (imageWriterFormat == splashModeMono8) {
+        SplashColorPtr row;
+        unsigned char **row_pointers = new unsigned char*[height];
+        row = data;
 
-        if (!writer->writeRow(&row)) {
-          delete[] row;
+        for (int y = 0; y < height; ++y) {
+          row_pointers[y] = row;
+          row += rowSize;
+        }
+        if (!writer->writePointers(row_pointers, height)) {
+          delete[] row_pointers;
           return splashErrGeneric;
         }
+        delete[] row_pointers;
+      }
+      else if (imageWriterFormat == splashModeRGB8) {
+        unsigned char *row = new unsigned char[3 * width];
+        for (int y = 0; y < height; y++) {
+          // Convert into a PNG row
+          for (int x = 0; x < width; x++) {
+            row[3*x] = data[y * rowSize + x];
+            row[3*x+1] = data[y * rowSize + x];
+            row[3*x+2] = data[y * rowSize + x];
+          }
+
+          if (!writer->writeRow(&row)) {
+            delete[] row;
+            return splashErrGeneric;
+          }
+        }
+        delete[] row;
+      }
+      else {
+        // only splashModeMono8 or splashModeRGB8
+        return splashErrGeneric;
       }
-      delete[] row;
     }
     break;
     
     case splashModeMono1:
     {
-      unsigned char *row = new unsigned char[3 * width];
-      for (int y = 0; y < height; y++) {
-        // Convert into a PNG row
-        for (int x = 0; x < width; x++) {
-          getPixel(x, y, &row[3*x]);
-          row[3*x+1] = row[3*x];
-          row[3*x+2] = row[3*x];
-        }
+      if (imageWriterFormat == splashModeMono1) {
+        SplashColorPtr row;
+        unsigned char **row_pointers = new unsigned char*[height];
+        row = data;
 
-        if (!writer->writeRow(&row)) {
-          delete[] row;
+        for (int y = 0; y < height; ++y) {
+          row_pointers[y] = row;
+          row += rowSize;
+        }
+        if (!writer->writePointers(row_pointers, height)) {
+          delete[] row_pointers;
           return splashErrGeneric;
         }
+        delete[] row_pointers;
+      }
+      else if (imageWriterFormat == splashModeRGB8) {
+        unsigned char *row = new unsigned char[3 * width];
+        for (int y = 0; y < height; y++) {
+          // Convert into a PNG row
+          for (int x = 0; x < width; x++) {
+            getPixel(x, y, &row[3*x]);
+            row[3*x+1] = row[3*x];
+            row[3*x+2] = row[3*x];
+          }
+
+          if (!writer->writeRow(&row)) {
+            delete[] row;
+            return splashErrGeneric;
+          }
+        }
+        delete[] row;
+      }
+      else {
+        // only splashModeMono1 or splashModeRGB8
+        return splashErrGeneric;
       }
-      delete[] row;
     }
     break;
     
diff --git a/splash/SplashBitmap.h b/splash/SplashBitmap.h
index 4417af733..555425804 100644
--- a/splash/SplashBitmap.h
+++ b/splash/SplashBitmap.h
@@ -109,6 +109,7 @@ class SplashBitmap {
   Guchar *alpha;		// pointer to row zero of the alpha data
 				//   (always top-down)
   GooList *separationList; // list of spot colorants and their mapping functions
+  SplashColorMode imageWriterFormat; // input format of ImgWriter
 
   friend class Splash;
 };