diff --git a/src/HMT_Parser.c b/src/HMT_Parser.c
index 4848294..1d69e23 100644
--- a/src/HMT_Parser.c
+++ b/src/HMT_Parser.c
@@ -53,7 +53,6 @@ int readMaterial(HMT_MATERIAL *mat, FILE *hmt_src) {
 
 int readTexture(HMT_TEXTURE *tex, FILE *hmt_src) {
 	char u0,u1,bpp;
-	int color_rgba;
 	long pos;
 	RS_IMAGE_DESC desc;
 
@@ -68,7 +67,10 @@ int readTexture(HMT_TEXTURE *tex, FILE *hmt_src) {
 	fread(&bpp, 1, 1, hmt_src);
 	fread(&(tex->image.type_), 1, 1, hmt_src);
 	fread(&u1, 1, 1, hmt_src);
-	fread(&color_rgba, 4, 1, hmt_src);
+	fread(&(tex->image.alpha_color._red), 1, 1, hmt_src);
+	fread(&(tex->image.alpha_color._green), 1, 1, hmt_src);
+	fread(&(tex->image.alpha_color._blue), 1, 1, hmt_src);
+	fread(&(tex->image.alpha_color._alpha), 1, 1, hmt_src);
 
 	pos = ftell(hmt_src);
 	fseek(hmt_src, tex->textureName_offset, SEEK_SET);
@@ -81,11 +83,13 @@ int readTexture(HMT_TEXTURE *tex, FILE *hmt_src) {
 	tex->image.width = tex->width;
 	tex->image.height = tex->height;
 
+	printf("\n");
 	printf("Texture name: %s\n", tex->name);
 	printf("Size w: %ld	h: %ld\n", tex->width, tex->height);
 	printf("Texture subtype: %d\n", tex->image.type_);
 	printf("Palette offset: %d\n", tex->palette_offset);
 	printf("Data offset: %d\n", tex->data_offset);
+	printf("Transparent color (RGB): %X %X %X\n", tex->image.alpha_color._red, tex->image.alpha_color._green, tex->image.alpha_color._blue);
 	printf("u0: %d	u1: %d\n", u0, u1);
 
 	if (tex->palette_offset > 0) {
diff --git a/src/Image_Exporter.c b/src/Image_Exporter.c
index f430f3c..7093b2e 100644
--- a/src/Image_Exporter.c
+++ b/src/Image_Exporter.c
@@ -8,7 +8,7 @@ int saveToPNG(RS_IMAGE *img, char *tex_name) {
 	png_infop info_ptr = NULL;
 	size_t x,y;
 	png_byte **row_ptrs = NULL;
-	PIXEL *pixel = NULL;
+	PIXEL_A *pixel = NULL;
 	//int pixel_size = 3;
 	//int depth = 8;		//bit par color channel (RGB)
 
@@ -28,12 +28,12 @@ int saveToPNG(RS_IMAGE *img, char *tex_name) {
 	}
 
 	// Set image attributes
-	png_set_IHDR(png_ptr, info_ptr, img->width, img->height, 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+	png_set_IHDR(png_ptr, info_ptr, img->width, img->height, 8, PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
 
 	// Init PNG datas
 	row_ptrs = png_malloc(png_ptr, img->height * sizeof(png_byte *));
 	for (y=0; y<img->height; y++) {
-		png_byte *row = png_malloc(png_ptr, img->width*sizeof(PIXEL));
+		png_byte *row = png_malloc(png_ptr, img->width*sizeof(PIXEL_A));
 		row_ptrs[y] = row;
 		for (x=0; x<img->width; x++) {
 			pixel = pixelAt(img, x , y);
@@ -42,6 +42,7 @@ int saveToPNG(RS_IMAGE *img, char *tex_name) {
 			*row++ = pixel->_red;
 			*row++ = pixel->_green;
 			*row++ = pixel->_blue;
+			*row++ = pixel->_alpha;
 		}
 	}
 	/*
diff --git a/src/RS_images.c b/src/RS_images.c
index f11946c..4713c29 100644
--- a/src/RS_images.c
+++ b/src/RS_images.c
@@ -1,5 +1,7 @@
 #include "RS_images.h"
 
+#define PIXEL_MEMBERS_NBR 4
+
 
 int getPaletteFromFile(RS_IMAGE *img, FILE *f) {
 	int entries = img->paletteEntries;
@@ -51,9 +53,9 @@ void decodePixels(RS_IMAGE *img) {
 		break;
 	case 4:
 		if (img->paletteEntries == 0) {
-			size = sizeof(PIXEL) * img->height * img->width;
+			size = sizeof(PIXEL_A) * img->height * img->width;
 			img->pixels = calloc(1, size);
-			convert4bitsGreyto8bitsRGB(img->samples, img->pixels, div(size,3).quot);
+			convert4bitsGreyto8bitsRGB(img->samples, img->pixels, div(size, PIXEL_MEMBERS_NBR).quot, &(img->alpha_color));
 		} else if (img->paletteEntries == 16) {
 			size = img->width * img->height;
 			img->pixels = calloc(1, size*3);
@@ -81,7 +83,17 @@ void decodePixels(RS_IMAGE *img) {
 	}
 }
 
-void convert4bitsGreyto8bitsRGB(unsigned char *samples_tab, PIXEL *pixels_tab, int sampling) {
+int isTransparentColor(PIXEL_A *testColor, PIXEL_A *transp_color) {
+	if (transp_color == NULL || testColor == NULL) return -2;
+
+	if (!(testColor->_red == transp_color->_red)) return -1;
+	if (!(testColor->_green == transp_color->_green)) return -1;
+	if (!(testColor->_blue == transp_color->_blue)) return -1;
+
+	return 0;
+}
+
+void convert4bitsGreyto8bitsRGB(unsigned char *samples_tab, PIXEL_A *pixels_tab, int sampling, PIXEL_A *transp_color) {
 	int i;
 	unsigned char v;
 
@@ -90,9 +102,11 @@ void convert4bitsGreyto8bitsRGB(unsigned char *samples_tab, PIXEL *pixels_tab, i
 		pixels_tab[i*2]._red = div((v >> 4 & 0xF) * 256, 16).quot;
 		pixels_tab[i*2]._green = div((v >> 4 & 0xF) * 256, 16).quot;
 		pixels_tab[i*2]._blue = div((v >> 4 & 0xF) * 256, 16).quot;
+		if (isTransparentColor(&(pixels_tab[i*2]), transp_color) == 0) pixels_tab[i*2]._alpha = 0xFF - transp_color->_alpha; else pixels_tab[i*2]._alpha = 0xFF;		// Test if color is a transparent color and adjust alpha layer
 		pixels_tab[i*2+1]._red = div((v & 0xF) * 256, 16).quot;
 		pixels_tab[i*2+1]._green = div((v & 0xF) * 256, 16).quot;
 		pixels_tab[i*2+1]._blue = div((v & 0xF) * 256, 16).quot;
+		if (isTransparentColor(&(pixels_tab[i*2+1]), transp_color) == 0) pixels_tab[i*2+1]._alpha = 0xFF - transp_color->_alpha; else pixels_tab[i*2+1]._alpha = 0xFF;		// Test if color is a transparent color and adjust alpha layer
 	}
 }
 
@@ -123,7 +137,7 @@ void useOddBytes(unsigned char *src, unsigned char *dst, int size) {
 	}
 }
 
-PIXEL *pixelAt(RS_IMAGE *img, int posX , int posY) {
+PIXEL_A *pixelAt(RS_IMAGE *img, int posX , int posY) {
 	return img->pixels + img->width * posY + posX;
 }
 
diff --git a/src/RS_images.h b/src/RS_images.h
index d3be214..b8c1495 100644
--- a/src/RS_images.h
+++ b/src/RS_images.h
@@ -18,7 +18,17 @@
 /////////////////////////////
 
 /**
- * @brief RGB pixel structure, used to store datas for implementation inside PNG files
+ * @brief RGBA pixel structure, used to store datas for implementation inside PNG files.
+ */
+typedef struct PixelRGBA {
+	unsigned char _red;
+	unsigned char _green;
+	unsigned char _blue;
+	unsigned char _alpha;
+}PIXEL_A;
+
+/**
+ * @brief RGB pixel structure, used to store datas for implementation inside PNG files, optimised version without alpha channel support.
  */
 typedef struct PixelRGB {
 	unsigned char _red;
@@ -35,7 +45,8 @@ typedef struct RSImage {
 	unsigned char type_;				/**< Image type (0 = RBG/4bits per pixel, 1 = RBG/8bpp, 3 = RGBA/32bpp , 4 = grayscale/4bpp, 5 = grayscale/8bpp */
 	unsigned char sampleBits;			/**< Bits per samble */
 	int paletteEntries;
-	PIXEL *pixels;						/**< Image pixels list, managed like an array and declared as a pointer */
+	PIXEL_A alpha_color;
+	PIXEL_A *pixels;						/**< Image pixels list, managed like an array and declared as a pointer */
 	unsigned char *samples;				/**< Image samples list managed like an array and declared as a pointer */
 	unsigned char palette[256][3];		/**< Image palette definition */					//TODO: Create union struct type instead
 }RS_IMAGE;
@@ -43,7 +54,6 @@ typedef struct RSImage {
 typedef struct RSImage_desc {
 	int palette_enties;
 	int sample_bits;
-	//char alpha;
 }RS_IMAGE_DESC;
 
 
@@ -51,12 +61,13 @@ typedef struct RSImage_desc {
 ///// Declare functions /////
 /////////////////////////////
 RS_IMAGE_DESC getImageDescFromType(unsigned char type);		//TODO: Optimise function
-void convert4bitsGreyto8bitsRGB(unsigned char *samples_tab, PIXEL *pixels_tab, int sampling);
+int isTransparentColor(PIXEL_A *testColor, PIXEL_A *transp_color);
+void convert4bitsGreyto8bitsRGB(unsigned char *samples_tab, PIXEL_A *pixels_tab, int sampling, PIXEL_A *transp_color);
 void unpack4To24bitsRGB(unsigned char *samples_tab, unsigned char *pixels_tab, int size, unsigned char pal[256][3]);
 void unpack8To24bitsRGB(unsigned char *samples_tab, unsigned char *pixels_tab, int size, unsigned char pal[256][3]);
 void useOddBytes(unsigned char *src, unsigned char *dst, int size);
 void decodePixels(RS_IMAGE *img);
-PIXEL *pixelAt(RS_IMAGE *img, int posX , int posY);
+PIXEL_A *pixelAt(RS_IMAGE *img, int posX , int posY);
 int getPaletteFromFile(RS_IMAGE *img, FILE *f);
 int getSamplesFromFile(RS_IMAGE *img, FILE *f);