diff --git a/engines/grim/bitmap.cpp b/engines/grim/bitmap.cpp
index 9f35022eafc..9a8dc9140c3 100644
--- a/engines/grim/bitmap.cpp
+++ b/engines/grim/bitmap.cpp
@@ -53,7 +53,7 @@ Bitmap::Bitmap(const char *fname, const char *data, int len) :
 	_y = READ_LE_UINT32(data + 24);
 //  _transparentColor = READ_LE_UINT32(data + 28);
 	_format = READ_LE_UINT32(data + 32);
-//  _numBits = READ_LE_UINT32(data + 36);
+	_bpp = READ_LE_UINT32(data + 36);
 //  _blueBits = READ_LE_UINT32(data + 40);
 //  _greenBits = READ_LE_UINT32(data + 44);
 //  _redBits = READ_LE_UINT32(data + 48);
@@ -67,10 +67,10 @@ Bitmap::Bitmap(const char *fname, const char *data, int len) :
 	_data = new char *[_numImages];
 	int pos = 0x88;
 	for (int i = 0; i < _numImages; i++) {
-		_data[i] = new char[2 * _width * _height];
+		_data[i] = new char[_bpp/8 * _width * _height];
 		if (codec == 0) {
-			memcpy(_data[i], data + pos, 2 * _width * _height);
-			pos += 2 * _width * _height + 8;
+			memcpy(_data[i], data + pos, _bpp/8 * _width * _height);
+			pos += _bpp/8 * _width * _height + 8;
 		} else if (codec == 3) {
 			int compressed_len = READ_LE_UINT32(data + pos);
 			decompress_codec3(data + pos + 4, _data[i]);
@@ -88,7 +88,7 @@ Bitmap::Bitmap(const char *fname, const char *data, int len) :
 	g_driver->createBitmap(this);
 }
 
-Bitmap::Bitmap(const char *data, int w, int h, const char *fname) : Object() {
+Bitmap::Bitmap(const char *data, int w, int h, int bpp, const char *fname) : Object() {
 	_fname = fname;
 	if (gDebugLevel == DEBUG_BITMAPS || gDebugLevel == DEBUG_NORMAL || gDebugLevel == DEBUG_ALL)
 		printf("New bitmap loaded: %s\n", fname);
@@ -102,10 +102,11 @@ Bitmap::Bitmap(const char *data, int w, int h, const char *fname) : Object() {
 	_format = 1;
 	_numTex = 0;
 	_texIds = NULL;
+	_bpp = bpp;
 	_hasTransparency = false;
 	_data = new char *[_numImages];
-	_data[0] = new char[2 * _width * _height];
-	memcpy(_data[0], data, 2 * _width * _height);
+	_data[0] = new char[_bpp/8 * _width * _height];
+	memcpy(_data[0], data, _bpp/8 * _width * _height);
 	g_driver->createBitmap(this);
 }
 
diff --git a/engines/grim/bitmap.h b/engines/grim/bitmap.h
index 289db615825..adf5e647563 100644
--- a/engines/grim/bitmap.h
+++ b/engines/grim/bitmap.h
@@ -36,7 +36,7 @@ class Bitmap : public Object {
 public:
 	// Construct a bitmap from the given data.
 	Bitmap(const char *filename, const char *data, int len);
-	Bitmap(const char *data, int width, int height, const char *filename);
+	Bitmap(const char *data, int width, int height, int bpp, const char *filename);
 	Bitmap();
 
 	const char *filename() const { return _fname.c_str(); }
@@ -69,6 +69,7 @@ public:
 	int _width, _height, _x, _y;
 	int _format;
 	int _numTex;
+	int _bpp;
 	void *_texIds;
 	bool _hasTransparency;
 	char _filename[32];
diff --git a/engines/grim/gfx_opengl.cpp b/engines/grim/gfx_opengl.cpp
index 5652988e91e..964baf3b990 100644
--- a/engines/grim/gfx_opengl.cpp
+++ b/engines/grim/gfx_opengl.cpp
@@ -461,26 +461,34 @@ void GfxOpenGL::createBitmap(Bitmap *bitmap) {
 		textures = (GLuint *)bitmap->_texIds;
 		glGenTextures(bitmap->_numTex * bitmap->_numImages, textures);
 
-		byte *texData = new byte[4 * bitmap->_width * bitmap->_height];
+		byte *texData = 0;
+		byte *texOut = 0;
 
 		for (int pic = 0; pic < bitmap->_numImages; pic++) {
-			// Convert data to 32-bit RGBA format
-			byte *texDataPtr = texData;
-			uint16 *bitmapData = reinterpret_cast<uint16 *>(bitmap->_data[pic]);
-			for (int i = 0; i < bitmap->_width * bitmap->_height; i++, texDataPtr += 4, bitmapData++) {
-				uint16 pixel = *bitmapData;
-				int r = pixel >> 11;
-				texDataPtr[0] = (r << 3) | (r >> 2);
-				int g = (pixel >> 5) & 0x3f;
-				texDataPtr[1] = (g << 2) | (g >> 4);
-				int b = pixel & 0x1f;
-				texDataPtr[2] = (b << 3) | (b >> 2);
-				if (pixel == 0xf81f) { // transparent
-					texDataPtr[3] = 0;
-					bitmap->_hasTransparency = true;
-				} else {
-					texDataPtr[3] = 255;
+			if (bitmap->_bpp == 16) {
+				if (texData == 0)
+					texData = new byte[4 * bitmap->_width * bitmap->_height];
+				// Convert data to 32-bit RGBA format
+				byte *texDataPtr = texData;
+				uint16 *bitmapData = reinterpret_cast<uint16 *>(bitmap->_data[pic]);
+				for (int i = 0; i < bitmap->_width * bitmap->_height; i++, texDataPtr += 4, bitmapData++) {
+					uint16 pixel = *bitmapData;
+					int r = pixel >> 11;
+					texDataPtr[0] = (r << 3) | (r >> 2);
+					int g = (pixel >> 5) & 0x3f;
+					texDataPtr[1] = (g << 2) | (g >> 4);
+					int b = pixel & 0x1f;
+					texDataPtr[2] = (b << 3) | (b >> 2);
+					if (pixel == 0xf81f) { // transparent
+						texDataPtr[3] = 0;
+						bitmap->_hasTransparency = true;
+					} else {
+						texDataPtr[3] = 255;
+					}
 				}
+				texOut = texData;
+			} else {
+				texOut = (byte *)bitmap->_data[pic];
 			}
 
 			for (int i = 0; i < bitmap->_numTex; i++) {
@@ -505,7 +513,7 @@ void GfxOpenGL::createBitmap(Bitmap *bitmap) {
 					textures = (GLuint *)bitmap->_texIds;
 					glBindTexture(GL_TEXTURE_2D, textures[cur_tex_idx]);
 					glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE,
-						texData + (y * 4 * bitmap->_width) + (4 * x));
+						texOut + (y * 4 * bitmap->_width) + (4 * x));
 					cur_tex_idx++;
 				}
 			}
diff --git a/engines/grim/grim.h b/engines/grim/grim.h
index 26967f22850..e255266bd23 100644
--- a/engines/grim/grim.h
+++ b/engines/grim/grim.h
@@ -153,7 +153,7 @@ public:
 		return b;
 	}
 	Bitmap *registerBitmap(const char *data, int width, int height, const char *filename) {
-		Bitmap *b = new Bitmap(data, width, height, filename);
+		Bitmap *b = new Bitmap(data, width, height, 16, filename);
 		_bitmaps.push_back(b);
 		return b;
 	}