diff --git a/src/osgPlugins/pnm/ReaderWriterPNM.cpp b/src/osgPlugins/pnm/ReaderWriterPNM.cpp
index 864be6f68..5da6bb9f6 100644
--- a/src/osgPlugins/pnm/ReaderWriterPNM.cpp
+++ b/src/osgPlugins/pnm/ReaderWriterPNM.cpp
@@ -22,16 +22,30 @@ template <class T>
     unsigned char* read_bitmap_ascii(std::istream& fin, int width, int height)
 {
     T* data = new T[width*height];
+    T* end = data + width*height;
 
+    int x = 0;
+    T* dst = end - width;
+    int value = 0;
 
+    while(dst >= data)
     {
+        fin >> value;
         if (!fin.good())
         {
             delete [] data;
             return NULL;
         }
 
+        // place value in the image. 0 is white and anything else is black.
+        *(dst++) = value ? 0 : 255;
+
+        // At end of each row, jump back two rows
+        ++x;
+        if (x == width)
         {
+            x = 0;
+            dst -= 2*width;
         }
     }
 
@@ -39,11 +53,19 @@ template <class T>
 }
 
 template <class T>
+    unsigned char* read_grayscale_ascii(std::istream& fin, int width, int height, int max_value)
 {
     T* data = new T[width*height];
+    T* end = data + width*height;
 
+    int x = 0;
+    T* dst = end - width;
+    int value = 0;
+    float max = (sizeof(T) == 1) ? 255.0 : 65535.0;
 
+    while(dst >= data)
     {
+        fin >> value;
         if (!fin.good())
         {
             delete [] data;
@@ -51,17 +73,34 @@ template <class T>
         }
 
         // place value in the image
+        *(dst++) = T(float(value)/float(max_value)*max);
+
+        // At end of each row, jump back two rows
+        ++x;
+        if (x == width)
+        {
+            x = 0;
+            dst -= 2*width;
+        }
     }
 
     return reinterpret_cast<unsigned char*>(data);
 }
 
 template <class T>
+    unsigned char* read_color_ascii(std::istream& fin, int width, int height, int max_value)
 {
     T* data = new T[3*width*height];
+    T* end = data + 3*width*height;
 
+    int x = 0;
+    T* dst = end - 3*width;
+    int value = 0;
+    float max = (sizeof(T) == 1) ? 255.0 : 65535.0;
 
+    while(dst >= data)
     {
+        fin >> value;
         if (!fin.good())
         {
             delete [] data;
@@ -69,6 +108,15 @@ template <class T>
         }
 
         // place value in the image
+        *(dst++) = T(float(value)/float(max_value)*max);
+
+        // At end of the row, jump back two rows
+        ++x;
+        if (x == width*3)
+        {
+            x = 0;
+            dst -= 6*width;
+        }
     }
 
     return reinterpret_cast<unsigned char*>(data);
@@ -79,6 +127,7 @@ template <class T>
 {
     T* data = new T[width*height];
 
+    for(int y = height-1; y >= 0; --y)
     {
         T* dst = data + (y+0)*width;
         T* end = data + (y+1)*width;
@@ -107,30 +156,55 @@ template <class T>
 template <class T>
     unsigned char* read_grayscale_binary(std::istream& fin, int width, int height)
 {
+    T* data = new T[width*height];
 
+    for(int y = height-1; y >= 0; --y)
     {
+        T* dst = data + y*width;
+        fin.read((char*)dst, sizeof(T)*width);
+        if (!fin.good())
+        {
+            delete [] data;
+            return NULL;
+        }
     }
 
     // if the machine is little endian swap the bytes around
     if (sizeof(T) == 2 && getCpuByteOrder() == osg::LittleEndian)
     {
+        unsigned char *bs = reinterpret_cast<unsigned char *>(data);
+        unsigned char *end = bs + sizeof(T)*width*height;
+        for (; bs < end; bs += 2)
         {
             std::swap(bs[0], bs[1]);
         }
     }
 
+    return reinterpret_cast<unsigned char *>(data);
 }
 
 template <class T>
     unsigned char* read_color_binary(std::istream& fin, int width, int height)
 {
+    T* data = new T[3*width*height];
 
+    for(int y = height-1; y >= 0; --y)
     {
+        T* dst = data + y*3*width;
+        fin.read((char*)dst, sizeof(T)*3*width);
+        if (!fin.good())
+        {
+            delete [] data;
+            return NULL;
+        }
     }
 
     // if the machine is little endian swap the bytes around
     if (sizeof(T) == 2 && getCpuByteOrder() == osg::LittleEndian)
     {
+        unsigned char *bs = reinterpret_cast<unsigned char *>(data);
+        unsigned char *end = bs + sizeof(T)*3*width*height;
+        for (; bs < end; bs+=2)
         {
             std::swap(bs[0], bs[1]);
         }
@@ -225,9 +299,11 @@ class ReaderWriterPNM : public osgDB::ReaderWriter
                 {
                     case 2:    // grayscale ascii
                         pixelFormat = GL_LUMINANCE;
+                        data = read_grayscale_ascii<unsigned short>(fin, width, height, max_value);
                         break;
                     case 3:    // color ascii
                         pixelFormat = GL_RGB;
+                        data = read_color_ascii<unsigned short>(fin, width, height, max_value);
                         break;
                     case 5:    // grayscale binary
                         pixelFormat = GL_LUMINANCE;
@@ -237,6 +313,9 @@ class ReaderWriterPNM : public osgDB::ReaderWriter
                         pixelFormat = GL_RGB;
                         data = read_color_binary<unsigned short>(fin, width, height);
                         break;
+                    default:
+                        return ReadResult::ERROR_IN_READING_FILE;
+                        break;
                 }
             }
             else
@@ -250,9 +329,11 @@ class ReaderWriterPNM : public osgDB::ReaderWriter
                         break;
                     case 2:    // grayscale ascii
                         pixelFormat = GL_LUMINANCE;
+                        data = read_grayscale_ascii<unsigned char>(fin, width, height, max_value);
                         break;
                     case 3:    // color ascii
                         pixelFormat = GL_RGB;
+                        data = read_color_ascii<unsigned char>(fin, width, height, max_value);
                         break;
                     case 4:    // bitmap binary
                         pixelFormat = GL_LUMINANCE;
@@ -266,6 +347,9 @@ class ReaderWriterPNM : public osgDB::ReaderWriter
                         pixelFormat = GL_RGB;
                         data = read_color_binary<unsigned char>(fin, width, height);
                         break;
+                    default:
+                        return ReadResult::ERROR_IN_READING_FILE;
+                        break;
                 }
             }