diff --git a/src/m_png.cpp b/src/m_png.cpp
index dd2e46970..1e1a331af 100644
--- a/src/m_png.cpp
+++ b/src/m_png.cpp
@@ -103,7 +103,7 @@ static inline void MakeChunk (void *where, DWORD type, size_t len);
 static inline void StuffPalette (const PalEntry *from, BYTE *to);
 static bool WriteIDAT (FILE *file, const BYTE *data, int len);
 static void UnfilterRow (int width, BYTE *dest, BYTE *stream, BYTE *prev, int bpp);
-static void UnpackPixels (int width, int bytesPerRow, int bitdepth, const BYTE *rowin, BYTE *rowout);
+static void UnpackPixels (int width, int bytesPerRow, int bitdepth, const BYTE *rowin, BYTE *rowout, bool grayscale);
 
 // EXTERNAL DATA DECLARATIONS ----------------------------------------------
 
@@ -604,7 +604,7 @@ bool M_ReadIDAT (FileReader *file, BYTE *buffer, int width, int height, int pitc
 				in = prev;
 				if (bitdepth < 8)
 				{
-					UnpackPixels (passwidth, bytesPerRowIn, bitdepth, in, adam7buff[2]);
+					UnpackPixels (passwidth, bytesPerRowIn, bitdepth, in, adam7buff[2], colortype == 0);
 					in = adam7buff[2];
 				}
 				// Distribute pixels into the output buffer
@@ -688,7 +688,7 @@ bool M_ReadIDAT (FileReader *file, BYTE *buffer, int width, int height, int pitc
 		passpitch = pitch << interlace;
 		for (curr = buffer + pitch * interlace; curr <= prev; curr += passpitch)
 		{
-			UnpackPixels (width, bytesPerRowIn, bitdepth, curr, curr);
+			UnpackPixels (width, bytesPerRowIn, bitdepth, curr, curr, colortype == 0);
 		}
 	}
 	return true;
@@ -1155,7 +1155,7 @@ void UnfilterRow (int width, BYTE *dest, BYTE *row, BYTE *prev, int bpp)
 //
 //==========================================================================
 
-static void UnpackPixels (int width, int bytesPerRow, int bitdepth, const BYTE *rowin, BYTE *rowout)
+static void UnpackPixels (int width, int bytesPerRow, int bitdepth, const BYTE *rowin, BYTE *rowout, bool grayscale)
 {
 	const BYTE *in;
 	BYTE *out;
@@ -1242,4 +1242,26 @@ static void UnpackPixels (int width, int bytesPerRow, int bitdepth, const BYTE *
 		}
 		break;
 	}
+
+	// Expand gray scale to 8bpp
+	if(grayscale)
+	{
+		out = rowout + width;
+		while(--out >= rowout)
+		{
+			switch(bitdepth)
+			{
+				case 1:
+					*out *= 0xFF;
+					break;
+				case 2:
+					*out |= (*out<<2)|(*out<<4)|(*out<<6);
+					break;
+				case 4:
+					*out |= (*out<<4);
+					break;
+				default: break;
+			}
+		}
+	}
 }
diff --git a/src/textures/pngtexture.cpp b/src/textures/pngtexture.cpp
index 8120df968..7927c0a93 100644
--- a/src/textures/pngtexture.cpp
+++ b/src/textures/pngtexture.cpp
@@ -297,33 +297,17 @@ FPNGTexture::FPNGTexture (FileReader &lump, int lumpnum, const FString &filename
 	case 0:		// Grayscale
 		if (!bAlphaTexture)
 		{
-			BYTE *GrayMapSrc;
-			switch(BitDepth)
-			{
-				default:
-					GrayMapSrc = GrayMap;
-					break;
-				case 4:
-					GrayMapSrc = GrayMap4bit;
-					break;
-				case 2:
-					GrayMapSrc = GrayMap2bit;
-					break;
-				case 1:
-					GrayMapSrc = GrayMap1bit;
-					break;
-			}
 			if (colortype == 0 && havetRNS && trans[0] != 0)
 			{
 				bMasked = true;
-				PaletteSize = 1<<BitDepth;
-				PaletteMap = new BYTE[PaletteSize];
-				memcpy (PaletteMap, GrayMapSrc, 256);
+				PaletteSize = 256;
+				PaletteMap = new BYTE[256];
+				memcpy (PaletteMap, GrayMap, 256);
 				PaletteMap[trans[0]] = 0;
 			}
 			else
 			{
-				PaletteMap = GrayMapSrc;
+				PaletteMap = GrayMap;
 			}
 		}
 		break;
diff --git a/src/textures/texture.cpp b/src/textures/texture.cpp
index eb959c778..093bf303b 100644
--- a/src/textures/texture.cpp
+++ b/src/textures/texture.cpp
@@ -56,29 +56,13 @@ struct TexCreateInfo
 };
 
 BYTE FTexture::GrayMap[256];
-BYTE FTexture::GrayMap4bit[16];
-BYTE FTexture::GrayMap2bit[4];
-BYTE FTexture::GrayMap1bit[2];
 
 void FTexture::InitGrayMap()
 {
 	for (int i = 0; i < 256; ++i)
 	{
 		GrayMap[i] = ColorMatcher.Pick (i, i, i);
-		if(i < 16)
-		{
-			const int i4 = i|(i<<4);
-			GrayMap4bit[i] = ColorMatcher.Pick (i4, i4, i4);
-		}
-		if(i < 4)
-		{
-			const int i2 = i|(i<<2)|(i<<4)|(i<<6);
-			GrayMap4bit[i] = ColorMatcher.Pick (i2, i2, i2);
-		}
 	}
-
-	GrayMap1bit[0] = ColorMatcher.Pick (0, 0, 0);
-	GrayMap1bit[1] = ColorMatcher.Pick (255, 255, 255);
 }
 
 FTexture *IMGZTexture_TryCreate(FileReader &, int lumpnum);
diff --git a/src/textures/textures.h b/src/textures/textures.h
index a0abaf54f..100ba31e9 100644
--- a/src/textures/textures.h
+++ b/src/textures/textures.h
@@ -283,9 +283,6 @@ public:
 protected:
 	WORD Width, Height, WidthMask;
 	static BYTE GrayMap[256];
-	static BYTE GrayMap4bit[16];
-	static BYTE GrayMap2bit[4];
-	static BYTE GrayMap1bit[2];
 	FNativeTexture *Native;
 
 	FTexture (const char *name = NULL, int lumpnum = -1);