diff --git a/PVRTCEncoder/src/Image.cpp b/PVRTCEncoder/src/Image.cpp
index cbca9d3..1cc997f 100644
--- a/PVRTCEncoder/src/Image.cpp
+++ b/PVRTCEncoder/src/Image.cpp
@@ -252,7 +252,11 @@ void Image::ExpandTo8888() {
   }
 }
 
-const Pixel &Image::GetPixel(int32 i, int32 j, EWrapMode wrapMode) {
+const Pixel &Image::GetPixel(int32 i, int32 j, EWrapMode wrapMode) const {
+  return m_Pixels[GetPixelIndex(i, j, wrapMode)];
+}
+
+const uint32 Image::GetPixelIndex(int32 i, int32 j, EWrapMode wrapMode) const {
   while(i < 0) {
     if(wrapMode == eWrapMode_Clamp) {
       i = 0;
diff --git a/PVRTCEncoder/src/Image.h b/PVRTCEncoder/src/Image.h
index 8550d2a..e7b35e6 100644
--- a/PVRTCEncoder/src/Image.h
+++ b/PVRTCEncoder/src/Image.h
@@ -87,7 +87,8 @@ class Image {
   Pixel *m_Pixels;
   Pixel *m_FractionalPixels;
 
-  const Pixel &GetPixel(int32 i, int32 j, EWrapMode wrapMode = eWrapMode_Clamp);
+  const uint32 GetPixelIndex(int32 i, int32 j, EWrapMode wrapMode = eWrapMode_Clamp) const;
+  const Pixel &GetPixel(int32 i, int32 j, EWrapMode wrapMode = eWrapMode_Clamp) const;
 };
 
 }  // namespace PVRTCC